What were the cheat mechanics Mike was talking about in the movie Rounders?

It appears that they make their own kind of names for some of their mechanics.

If you dig deep enough, there are new names for many the same move in every county and town around the world...Though I'm not actually sure what you're asking...What are other common names for these techniques, or how they're performed....as in your quote they list off the techniques they use and one can easily google/youtube them...

The techniques I recognise are likely different names for a few blind shuffles overhand run ups, and the double duke

Blind shuffles are any shuffle that a card mechanic uses to control and fake a shuffle. This is generally to keep cards at the bottom, or the top (or centre!) ...and in rare cases to keep the entire deck in it's original order. These can be used in different situations, however generally one will have 'stocked' or 'culled' the deck and controlled cards to the top or bottom, faked a cut and then will use a blind shuffle to keep the cards where they are. At this point one can use a bottom, second, or centre deal to pull the cards when required.

The mechanics grip is simply the 'standard' way of holding a deck, four fingers on the side, firmly in your hand and thumb over the top. It's often a 'tell' for other cheaters that the dealer might be more talented than they let on. This particular grip is generally the starting point one learns when following Erdnase methods, and well most cardistry things. Unless one happens to be Richard Turner. It's generally difficult to tell when someone is cheating...especially since the trivial techniques are very easy to learn.

I would suggest reading "The Expert at the Card Table" or hitting up your local Youtube if you want an in depth explanation at card cheating techniques.