There is a very good list by denofgeek:

• Early on, Wade discusses how horrible his father was. This is 2/3 on point to the comics. In the comics, there were three different takes on what Wade’s father was like. First there’s the Christopher Priest take, where Wade’s father was a lowlife who walked out on him when he was a child. Then Fabian Nicieza had his own version where Wade’s father was a strict, albeit well-meaning, military man who died trying to pull Wade away from hanging out with a dangerous crowd.

  Gerry Duggan later insisted that those were false memories. There was nothing especially wrong with Wade’s father, though Deadpool unknowingly killed him as part of a memory-wiping experiment.

• Deadpool prepares for his first job in the movie by listening to “X Gone Give it to You” by DMX, which was a prominent theme to the first movie.

• Deadpool popping out of a coffin to assassinate someone was done in Deadpool Team-Up #898, as part of an alliance with the Zapata Brothers.

• Deadpool’s frustration at being suicidal and being unable to see it through is a regular occurrence in the comics. The first movie’s earlier draft even had a segment dedicated to Wade trying to off himself again and again and constantly failing due to his healing factor.

• As an X-Men trainee, Deadpool wears an ugly team outfit over his own. This is similar to a story arc in Deadpool #16 from the Daniel Way run where Deadpool insisted on joining the X-Men.

• The red motor scooter Deadpool rides is actually a thing from the comics. He rode it around in Deadpool #68 and even appeared on the cover with it along with Taskmaster.

• Deadpool tries deflecting Cable’s bullets with his katanas at one point, only to realize that several of them made it through his torso. His movements are exactly like Wade Wilson’s swordplay in X-Men Origins: Wolverine.

• Towards the end of the movie, Deadpool is covered with ash and his red costume becomes gray. This ends up making him look like how he dresses in the Rick Remender X-Force series. Coincidentally, he joined the team in response to Cable’s supposed death.

• Vanessa did also die in the comics, albeit under very, very different circumstances. In Deadpool #59 by Frank Tieri and Georges Jeanty, Deadpool was given the order by Weapon X to kill Vanessa, otherwise known as the mutant Copycat. Deadpool refused and instead tried to defend her against their various soldiers. Vanessa ended up being mauled to death by Sabretooth and, much like the movie, died in Wade’s arms.

  

• Fun fact: for people who got to see early screenings of Deadpool 2, it came with a video of Deadpool begging us not to check Cable’s Wikipedia page because it’s too much of a mindfuck.

• Cable mentions his daughter’s name is Hope. Hope Summers is a character introduced in X-Men #205, created by Mike Carey and Chris Bachalo. After the events of M-Day and the near extinction of the mutant race (more on that later), Hope was the first baby born with the mutant gene. Cable found her and protected her, mainly from Bishop. Cable and Hope traveled through various eras with Cable raising Hope until she became a teenager. Eventually, she returned to the present.

• With Cable being played by Josh Brolin, there are at least two references to Brolin’s previous roles. Deadpool calls him “One-Eyed Willy,” a legendary pirate from The Goonies, which starred Brolin as Brand. The other is Deadpool calling him “Thanos,” what with that being his other huge comic movie role these days.

• Deadpool calls Cable “John Connor,” due to his similarities to, well, everything involving the Terminator franchise.

• Russell Collins, played by Julian Dennison, is essentially a hybrid of different characters.

  • In the comics, Firefist was introduced in X-Factor #1 by Bob Layton and Jackson Guice. A fit, white teen in slacks who physically looks nothing like his cinematic counterpart. He actually has more in common with his animated counterpart from the X-Men cartoon. Russell shares a lot in common with Johnny, a little boy who appeared briefly in Deadpool’s initial solo series. In Deadpool #58, a mutant boy’s fire powers went out of control and Weapon X (now with Deadpool as a member) went to go investigate. Deadpool was able to talk the boy down from his rampage, but Garrison Kane took advantage of the situation and murdered the kid, much to Deadpool’s fury.

  • Thematically, Russell is more based on Evan Sabahnur, codename Genesis. An incarnation of X-Force featuring Deadpool was sent on a mission to kill the reincarnation of Apocalypse. The target ended up being a child, who was being fed propaganda from Apocalypse cultists. Fantomex shot and killed the boy, which awakened nothing but disgust in Deadpool, as killing a kid was over the line for him.

• Deadpool rants about Domino's luck-based powers and how stupid they are, at one point claiming that such an idea would come from some guy who can’t even draw feet. This is an obvious reference to Deadpool and Domino’s co-creator Rob Liefeld, who is constantly made fun of for his difficulties in drawing convincing feet, which more often than not means seeing feet obscured or cropped out of his panels.

• Conversation between Juggernaut and Russell establishes that in the movies, Cain Marko and Charles Xavier are step-brothers and that Juggernaut wears the helmet to protect himself from his psychic attacks. The familial connection was completely ignored in X3, though the two only shared one scene.

• Juggernaut tearing Deadpool in half just may be a reference to the memorable opening sequence to Ultimate Wolverine vs. Hulk #1 where Hulk tore Wolverine in half in similar fashion. Hey, it wouldn’t be the only Hulk/Juggernaut comparison in this movie.

• Colossus vs. Juggernaut is a regular occurrence in X-Men lore. Much like in this movie, Juggernaut is a league above Colossus and tends to outfight him at every turn.

• Terry Crews’ Bedlam first appeared in the comic Factor X #1, created by John Francis Moore and Steve Epting. Bedlam doesn’t exactly get to do much in the movie, but the power set is accurate to how he’s portrayed in the comics.

• Zeitgeist (Axel Cluney) even being in this movie practically spells out the gag about X-Force’s fate. The character was introduced in X-Force #116, which was the beginning of the Peter Milligan/Mike Allred X-Force/X-Statix run. Like in the movie, he could spit acid vomit, but also like in the movie, he died in his first issue despite being treated as a big deal. In fact, a majority of X-Force were killed in that first issue.

• Vanisher, real name Telford Porter, was introduced in the second issue of X-Men. He has absolutely nothing to do with his cinematic counterpart, including powers. Comic Vanisher is a teleporter while the movie version is just invisible. Also, he was an X-Men villain and never a member of X-Force. And hey, turns out he’s Brad Pitt!

• Shatterstar, despite his limited screentime, dives deep into being exactly like his comic counterpart. Introduced in New Mutants #99 (a mere issue after Deadpool) by Nicieza and Liefeld, Shatterstar is both an alien and from the future. And he has those stupid double-katanas. Mojoworld was introduced in Longshot #1 and is a separate dimension run by a blobby TV producer with spider legs. This is now part of the X-Men Cinematic Unvierse.

• Black Tom Cassidy was introduced in X-Men #99 by Chris Claremont and Dave Cockrum. His wood/blast powers are kind of moot since he never actually does anything mutant-based in the movie. Black Tom is the brother of Banshee, but there’s no indication of their relationship in the film. In the comics, Black Tom fought Deadpool several times. Not only as a partner of Juggernaut, but also at a time when Deadpool was cycling through his “Black” villains in one adventure, such as Black Swan and Black Box. During the early days of X-Force, Cable gunned down Black Tom and almost killed him. Coincidentally, Black Tom only survived because Deadpool saved his life.

• Firefist’s rampage is covered by reporter Irene Merryweather. Introduced in Cable #48 by James Robinson and Jose Ladronn, Irene is a reporter who became a close friend to Cable.

• During the auditions segment, there’s a cartoon drawing of a cowgirl in the background. This is Outlaw, otherwise known as Inez Temple. Introduced during the Gail Simone Deadpool run, the mercenary mutant Outlaw had a couple flings with Deadpool and even married him briefly.

• The Ice Box is a prison located in Canada, introduced in Maverick #8.

• Russell’s orphanage is named in honor of “Essex,” most likely a reference to Nathanial Essex, otherwise known as Mr. Sinister. Essex was referenced in Days of Future Past’s ending and there’s been rumblings about having him appear in one of the upcoming movies.

• The mutant inhibitor collar was introduced in Days of Future Past. In the comics, it was introduced in X-Men #141.

• The orphanage features various posters promising that M-Day is coming. In the comics, M-Day was the event where Scarlet Witch – distraught over the events of House of M – used her powers to depower nearly every mutant in the world, leaving less than 200.

• You can spot Stan Lee twice in the movie. Once in a painting in the X-Mansion, and then again as a crazy graffiti mural as X-Force make their descent.

• The movie’s opening shot shows Deadpool’s music box in the form of Wolverine being impaled on a tree stump. This is how Wolverine died at the end of Logan. Deadpool also jokes that Logan wouldn’t have received that R-rating if the first Deadpool movie hadn’t already proven it could be done successfully.

• Deadpool briefly brings up comparisons to Passion of the Christ, namely how they’re the top two biggest money makers for R-rated movies. In terms of domestic, Passion of the Christ wins with $370 million to Deadpool’s $363 million, but worldwide, Deadpool has $801 million compared to Passion’s $622 million.

• Deadpool tries to excuse his lateness with Vanessa by claiming that he and another costumed guy had a big fight, but stopped once they found out their mothers are both named “Martha.” That’s an easy reference to the end of Batman v Superman: Dawn of Justice, where Batman suddenly pulls a 180 on his murderous opinion on Superman.

• In the first movie, Deadpool told Blind Al that he had a stash hidden of a bunch of cocaine and “the cure for blindness,” which at the time felt like him being a jerk mocking her. Turns out he literally had those things after all!

• Deadpool repeatedly talks about the X-Men member “Pigeonwings,” referring to Angel and the fact that having wings is kind of a dumb power when there are others who can fly without them.

• As Deadpool once again rants about how the only X-Men characters we appear to see are Colossus and Negasonic, there’s a quick shot of the current X-Men movie team meeting in a room as Beast (Nicholas Hoult) quietly closes the door before Deadpool can notice. This includes Xavier (James McAvoy), Quicksilver (Evan Peters), Storm (Alexandra Shipp), Cyclops (Tye Sheridan), and Nightcrawler (Kodi Smit-McPhee).

But why it's James McAvoy's version and not Patrick is discussed here:

Why did this actor play a cameo role in Deadpool 2?

• When Deadpool tries on the Cerebro head gear, he remarks it smells like Patrick Stewart, who of course originated the role of Charles Xavier in this franchise, appearing as the character a total of seven times, counting cameos.

• Deadpool’s speech where he decides to shoot up one of the orphanage employees is paraphrased from Colossus at the end of the first movie. The difference is that while he was straight-up ignoring him in the first movie when he shot somebody, this time he felt like he was genuinely doing the right thing.

• Upon losing his powers, Deadpool calls himself worthless like Hawkeye and his bow and arrow. Hawkeye has been regularly mocked for being considered the lamest movie Avenger.

• Deadpool describes Cable as having a Winter Soldier arm. In both the comics and Marvel Cinematic Universe, Bucky Barnes lost his arm during his faked death and had it replaced with a cybernetic limb. Cable’s arm is actually a metal parasite engulfing the flesh.

• Deadpool tosses out the iconic, “I’m Batman,” line, which is the go-to introduction for movie versions of that character.

• Deadpool remarks that Cable is so dark that he must be from the DC Universe. DC’s recent cinematic takes have been regularly criticized for being overly grim and colorless despite being centered around goddamn Superman. Fittingly, Ryan Reynolds and Josh Brolin have both starred in failed DC movies with Green Lantern and Jonah Hex.

• Deadpool names Domino “Black Black Widow,” doubling down on cracking jokes about white characters with “Black” in their name. Plus Domino is the token female hero and has the same basic abilities as Black Widow.

• Speaking of Black Widow, Deadpool tries to subdue Juggernaut by telling him, “The sun is getting real low.” This is how Black Widow would calm the Hulk into becoming Bruce Banner in Avengers: Age of Ultron.

• Dopinder is called “Brown Panther,” which is just a reference to Black Panther.

• In the mid-credits, Deadpool goes back in time to save certain people, but also takes time to enter X-Men Origins: Wolverine (2009) to riddle the original Deadpool with bullets. The mouthless Wade Wilson from this movie is considered a blight on the character’s history and while he got made fun of in the first Deadpool, this just goes farther into the absurd.

• Immediately after, Ryan Reynolds is shot to death before he can accept the role of Green Lantern (2011). That too is considered a big mistake in Reynolds’ acting career.

• After failing to fully fulfill his contract kill, Deadpool describes it as “mission accomplished” in the George W. Bush sense. In 2003, George W. Bush spoke onboard the USS Abraham Lincoln to announce the end of major military combat in Iraq. All the while, there was a massive “MISSION ACCOMPLISHED” banner in the background. The claims, both verbal and printed, seemed a bit shortsighted, to say the least.

• The movie Wade and Vanessa watch early on is the 1983 release Yentl starring Barbara Streisand. Streisand is Cable actor Josh Brolin's stepmom.

• And the song Wade keeps comparing "Papa Can You Hear Me?" to is, obviously, "Do You Want to Build a Snowman?" from Disney's megahit Frozen (2013).

• The opening credits include references to both James Bond movies and the iconic chair shot from Flashdance. It’s a natural callback to the comedic credits from the first movie, though with a more negative bend, such as how the first movie called the screenwriters “The Real Heroes” while this time they’re “The Real Villains.”

• When Deadpool wakes up in the X-Mansion and hijacks Xavier's wheelchair, he is wearing a T-Shirt that reads "Olivia and Meredith, Friends Furrrever." Those are the names of Taylor Swift's very furry cats. Even she herself acknowledged it.

• Deadpool calls Yukio “Pinkie Pie.” Pinkie Pie is a character from My Little Pony who, much like Deadpool, breaks the fourth wall.

• Colossus tells Russell, “Come quietly or there will be trouble.” Deadpool and Russell immediately point out that he’s ripping off RoboCop, which he also did in the first movie when he told Deadpool, “Dead or alive, you’re coming with me.”

• During this sequence, Deadpool also says, "Pump the hate brake, Fox and Friends." Which is a dig at well, the fearmongering and general unpleasantness of Fox News' morning show.

• At the Ice Box, Deadpool wonders what gang he’ll end up in and asks about the Sorting Hat. The Sorting Hat is the magical being from the Harry Potter books that chooses which group each Hogwarts student belongs in.

• At one point during his venting in the Ice Box, Russell says, "I'm going to burn Eddie Marsan alive." Clearly hanging out with Wade Wilson has had the Merc rub off on him, because Russell is also breaking the fourth wall here, as Eddie Marsan is the name of the actor who plays the pervert.

• Cable’s futuristic gun has a dial on it that goes from 1 to 11. This is a reference to This is Spinal Tap, as lead guitarist Nigel Tufnel (played by Christopher Guest) has his amps recalibrated from going up to 10 to 11 in volume because 11 is a higher number and therefore must be louder. He doesn't realize that the max volume is the max volume no matter what number you put on it.

• Weasel refers to Cable as “the time traveler’s wife’s husband.” The Time Traveler’s Wife is a novel by Audrey Niffenegger.

• Weasel calls it out, but Wade uncrossing and crossing his legs in order to show his gross baby crotch is a reference to Sharon Stone in Basic Instinct (1992). In the famous scene, she did the same move, only wearing a skirt with no underwear.

• Deadpool tries to win Colossus back by holding a tiny boombox up outside his window, just like John Cusack’s iconic pose from Say Anything (1989).

• We join a scene with Deadpool finishing his rant that Sisterhood of the Traveling Pants is pornography. That movie starred Ryan Reynolds' wife, Blake Lively.

• Deadpool notes that Russell has started dressing like the Unabomber. The 90s serial bomber Ted Kaczynski is mainly remembered for his police sketch that showed him wearing a hoodie and sunglasses.

• “Sweep the leg, Johnny!” is the command that the villain from Karate Kid is told when fighting Daniel in the climax.

• Cable firing the bullet that kills Deadpool (if at least briefly) is accompanied by the song "Tomorrow," a cloyingly saccharine (but catchy) tune from the Broadway musical Annie, which debuted in 1977. This is also set-up by the fact that Cable's daughter apparently had that song playing when she was killed in the future.

• Deadpool nicknames Negasonic “Eleven,” the name of the super-powered, shaved head girl from Stranger Things.

• Blink and you'll miss it, but a news ticker reports that "Christopher Plummer refuses role in Deadpool 2." This joke was in reference to Christopher Plummer Reshooting Kevin Spacey Scenes for 'All the Money in the World' due to the sexual allegation.

Few more from uproxx

• Dopinder (Karan Soni) has an ad for a travel service called Alpha Flight, telling us where Marvel’s team of Canadian heroes wound up in this cinematic universe.

• Opening credits to making fun of director David Leitch for the most infamous dead dog moment in film (John Wick). But the one it commits most to is a shout-out to, of all things, the notorious ’90s cheeseball thriller Basic Instinct, which not only memorably reenacts Sharon Stone’s flashing scene, but if you pay attention to the credits, you’ll notice they actually use Jerry Goldsmith’s score from the movie.

And additional one form : buzzfeed:

• The soundtrack for Deadpool 2 is full of bangers, but Deadpool gives Dolly Parton — who both stars in the 1980 film and sings the theme song of the same name that blasts over the montage of Deadpool killing people across the globe — a special shoutout: "Hit it, Dolly."

• There are a ton of Disney references in Deadpool 2, but this is the first. Deadpool uses it as a reference to prove that Deadpool 2 is, in fact, a family film, because every family movie starts with a vicious murder. The Lion King, Bambi and also refrenced Saw VII.

• Top Gun: Deadpool tells Dopinder, "Talk to me, Goose," in the cab in the beginning of the movie.

• Interview with the Vampire: Dopinder wants to become a contract killer, much like Claudia (Kirsten Dunst) when she first tasted blood, then looked up at Lestat's (Tom Cruise) smooth, handsome face and said, "I want some more."

• Deadpool jokes to Vanessa (Morena Baccarin) that he wants their kid to have one name, "like Cher." At the end of the movie, Deadpool uses Cable's time thingy to turn back time and "clean up the timeline." He returns to that same scene as Cher's "Turn Back Time" blasts and he screams, "We're definitely naming our kid Cher!"

• Star Wars: "Pretty sure Luke nailed her." Used by Deadpool as a incest joke.

• After Vanessa dies, Deadpool tells Weasel, "George Michael was right. I'm never gonna dance again. He's dead, too." "At least we still have Bowie." Reference to David Bowie.

• When Blind Al tells Deadpool, "You need to just keep living," after Vanessa dies, he responds, "Thank you, Matthew McConaughey, your words are a treasure."

• The Taylor Swift's kitten T-shirt design is a nod to Reynolds' criminally underrated role in 2005's Just Friends.

• Deadpool gets in a quick Lemonade joke with, "Like Beyoncé says, 'Please, please stop cheating on me."

• When Russell has his first meltdown and the X-Men try to calm him down, he refers to Negasonic by screaming, "Stay back, or Justin Bieber dies!"

• Much later, Deadpool calls Negasonic "Sabrina the Teenage Witch." This also seems in continuation of Ryan Reynolds tweet, which also been discussed here:

What does Sicario have to do with Sabrina the Teenage Witch?

• Deadpool refers to one of the abusive guards at Essex School for Mutant Rehabilitation as "Baldilocks" and the other as Jared Kushner, aka Donald Trump's son-in-law.

• When Deadpool discovers that Cable's from the future, he asks if dubstep's still a thing, makes a joke about his robotic arm, and asks "which Sharknado we're on."

• During one of Deadpool's many death scenes in Deadpool 2, his voiceover sadly says, "In every film, there's a moment when the hero hits rock bottom. In Cool Runnings, it was when John Candy's prize bobsled broke." Then continues, "In Human Centipede, it was when those people signed on to be in that movie."

• Again, there are some bangers on the Deadpool 2 soundtrack, but "Tomorrow" from the musical Annie plays on vinyl while Cable's family is murdered (proving it is truly a timeless classic), and again when Cable shoots Deadpool and he dies. So it gets a special spot.

• When Russell befriends the Juggernaut in prison, he tells him, "We're a team. We're like thugs, we're like gangsters. I'm like Tupac and you're like Ice Cube."

• Similar, near the end of the movie, Russell says: "Damn, it feels good to be a gangster", a line from the song with the same name by Geto Boys.

• When Bedlam (Terry Crews) joins X-Force, he says his powers can cause "anxiety, confusion, pain." Deadpool replies, "So, basically, you're Dave Matthews."

• Matt Damon makes a cameo as a redneck alongside Alan Tudyk, but what's even better is that Damon is credited as "Dickie Greenleaf" — the identity he steals from Jude Law in the 1999 movie The Talented Mr. Ripley.

• Mario Lopez: When Domino and Deadpool argue over whether luck is or isn't a super power, Deadpool replies, "Mario No-pez."

• When Cable's about to torture Weasel for information, Weasel responds that he doesn't do well with pain, and cried when they cancelled the 1998 TV show Felicity.

• Deadpool burns actor Josh Brolin's height when he describes Cable as, "Very short, 5'11", not like in the comics."

• I refuse to believe that anyone in a movie dying via wood chipper is NOT a reference to 1996's Fargo.

• When Juggernaut first appears, Deadpool fanboys out and mentions a few of his favorite Juggernaut-centric comics, including "Uncanny X-Men, Vol. 1, #183" and "X-Men Unlimited, Vol 1., #12."

• "Oh yeah, full Winnie the Pooh." We all know what scene that's from.

• "It's like he's a muppet from the waist down, but this time, you can see the muppet's dick." Yup.

• As he's dying, Deadpool bequeaths his Adventure Time watch to Domino.

From cbr

• After Deadpool has his legs torn off by the Juggernaut, he hangs out at his old place with Blind Al while they slowly grow back. During this time, he is wearing no pants, but the same shirt that the character of Chunk wears in The Goonies.

• When he draws his map of the planned attack, Russell’s prison number is listed as 24601. That is the famous prisoner number assigned to Jean Valjean in Victor Hugo’s Les Miserables. Hugh Jackman famously played that role in the 2012 musical adaptation of the novel.

• Deadpool plans out the attack on the prison convoy from the Ice Box that contains Russell Collins’ cell, Deadpool makes references to the fact that they are going to intercept the convoy while it was on the Duggan Parkway. This, of course, is a reference to writer Gerry Duggan, who only recently finished a long run as the writer of Deadpool’s regular series. Early in the film, when we see Deadpool slaughtering some bad guys, he first introduces himself to them as “Gail,” a possible reference to Gail Simone’s past run on Deadpool. In addition, during the actual attack on the prison convoy, we see a Hastings street sign. Christopher Hastings has written a number of Deadpool stories, as well.

• One of the names suggested for Deadpool's kid was Connor, which was a sad, but heartfelt reference to a kid that Deadpool himself, Ryan Reynolds, had met through the Make-A-Wish Foundation. Connor McGrath died a few years back, but not before being able to see a rough cut of the first Deadpool film. Reynolds wrote of him, “I’m grateful I got to orbit Connor’s world for a brief time.

From other sources

• A split-second glimpse around the Mutant prison known as the Ice Box gives us a look at some of the other mutants that might exist in this universe. One, in particular, seems to have giant bone spikes growing out of their back, a clear nod to the X-Man named Marrow who, strangely, was also referenced back in the first Deadpool during the experimentation scenes of Wade's origin story. So, she either survived that whole ordeal and wound up in prison or there are just two different mutants with the same incredibly unfortunate mutation running around. - gamespot.com

• In one scene where Deadpool is trying to work through his depression, he's speaking to Weasal (T.J. Miller) and reveals a wish to leave this planet and go to a planet of functional idiots, where he could be their Superman. comicbook.com

In the mid-credits scene where he time travels back to X-Men Origins: Wolverine to shoot that movie’s version of Deadpool, the joke is even more surreal because Ryan Reynolds plays both versions of Wade “Deadpool” Wilson.

You may have recognized Reynolds under all that makeup, and assumed the casting was simply a gag; but he actually is the guy who originally played that version of Deadpool.