What is the timeline of Black mirror?

The "consciousness cookies" technology has been a recurring theme lately.

Black Museum tied the episodes together, but they were already pretty much tied together due to the same technology being used the same way (the white knob, placed on a temple, and the spinning loading animation that keeps popping up). Black Museum simply made the connection stronger, e.g. by referring to the technology being tested in St Juniper's (a hospital), which is in reference to San Junipero (the episode title and name of the town where the woman/girls have a second youth).

However, that doesn't necessarily tie the other episodes (those without cookies) to the same timeline.
E.g. there's no reason to think the pilot episode is in any way meaningfully connected to the episodes with cookies.

There is some logic to the progression of the cookie-storyline. E.g. during USS Callister, transporting consciousness is not known about (the real world company merely markets it as a VR upgrade). We hear no mention of Z-eyes whatsoever.

However, during White Christmas, Z-eyes exist (and are commonplace), and cookie technology was known about sufficiently for (a) Jon Hamm having a career in cookie coercion and (b) the police using cookies for interrogation purposes.

That would mean USS Callister happens well before White Christmas.

But not all other episodes are as easily linked together, e.g. I doubt there is any way to know if San Junipero happens before or after White Christmas, as the events are completely separate.

Black Mirror is described as an anthology. All of the stories so far are stand-alone (although there is apparently some prospect of follow-ons to some stories). The fact that "Z-Eyes" (or "Z-Eye"-like technology), cookies (or cookie-like technology) appears in more than one episode is at most a writing/storytelling convenience. In episodes where they appear, usage isn't entirely consistent, so it can't be taken as evidence of a shared universe, so there is no "in-universe" timeline between the episodes.

"The Entire History of You" depicts an implanted or contact lens-like device used in conjunction with an implanted "grain" which only records/plays back what the wearer sees and hears, and seems to include a "block" feature. "White Christmas" depicts a similar contact lens-like device without a "grain", and has a "block" feature - the only real commonality with "The Entire History of You". The eye implants / contact lens-like devices in "Nosedive" appear to be little more than augmented reality display devices, simply overlaying helpful information on what the user sees (name, rating), and isn't depicted as having any other use. If taken to be an "earlier" form of the device, we should have seen ratings in "The Entire History of You" and/or "White Christmas", but we don't. The "cookie" technology in "White Christmas", a superficially similar implant to the "grain" works entirely differently - it builds a copy of the host consciousness, and appears to have no connection to the "Z-Eyes". "USS Calister" features copied consciousness (like cookies), but does it via DNA, making it an entirely different technology.

"The National Anthem", "The Waldo Moment", and "Shut Up and Dance" could all be set in the present day ("The National Anthem" might be slightly into the future because of its prospect of fooling the kidnapper with a simulation - that's just barely possible today). Even so, there is nothing to suggest that the depicted events occurred in the same universe.

Each story (so far) is set in its own universe, in the tradition of "Twilight Zone" and (for the most part) "Outer Limits". There are all sorts of "Easter egg" references between some of the stories (company names, logos, character names), as well as similar-looking or similar-functioning technologies, but that is all it is. Many of the episodes include things like televised news with bottom-of-the-screen crawls; they have to fill the crawls (or other screen space) with something (mostly not relevant to the current story) so they pluck characters/companies and extrapolated events from previously produced episodes. These references aren't indications of a shared universe/implied timeline. Most likely these things were chosen for their gag value.

Once upon a time, movies and episodes of TV shows were pretty much stand-alone. Movies didn't have sequels or prequels, and each episode of a TV show started out with its universe in exactly the same state as did the episode preceding or following - no character or story arcs spanning multiple episodes. Exceptions in "prime time" TV would have been pilots which had to establish the premise of the show, tweaks as new characters/actors enter a show or unavoidably mature within it, old ones leave, an aging show gets a makeover, and the occasional two-parter. Daytime soap operas were/have always been an exception also. In the movies, there were "serials" like "Flash Gordon" and "Buck Rogers" which theaters ran in installments before the featured movie. Then along came Superman (the 1977 Christopher Reeve version), Jaws, Star Wars, Indiana Jones, and the Star Trek movies (and its reboot) and suddenly we have franchises (like Marvel) with an explicit or implicit timeline connecting each release. Serialization is now almost ubiquitous in TV, especially dramas. Perhaps that has set up a false expectation, so when a show like Black Mirror comes along, we look for something which isn't really there.