I can mention some of the ones I’ve played:
USFIV: the combo system is link heavy, which results in shorter combos than most games, particularly air dashers. Also very ground bound. Focus attacks make zoning a bit more difficult than say Super turbo. Ultra meter gives you a sort of comeback mechanic of varying utility, usually based on the matchup or your character. Super meter is used most often for ex attacks and FADCs to extend combos, not usually super combos themselves.
Injustice: I just started playing this on a whim for my own enjoyment so I don’t know quite as much. Combo system is chain heavy. Unlike USFIV, there are attacks that bounce opponents off the ground, allowing you to continue combos after they fall. There is also more opportunity for juggles than USFIV. Interactables make the stage you select very important, and introduces a new twist to the footsies game in order to control the space around an interactable. I’ve found zoning to be more difficult, since most of the projectile attacks I’ve tried have a pretty long startup, making them easy to interrupt. Like SF, meter is mostly used to give a new property to special attacks more often than it’s used for a super. There’s more to say, but I can’t speak to how it’s used competitively. Mortal Kombat, to my understanding, is quite similar to this game, but doesn’t have interactables. I’m not a fan of MK, so maybe someone else can fill in the blanks here.
UMvC3: I mostly played vanilla MvC3, and am pretty ass, but I’ll do my best. Combo system is chain heavy, though it has a much different feel than Injustice. What separates this game is the team mechanic. You pick three characters, one is on screen, the other two are available to perform assist attacks or to tag in for the current character. Combos are usually optimized by launching opponents in the air and continuing the combo up there. The combos are usually quite long, sometimes draining entire life bars. IMO, this game is super hectic, with a fast pace and a lot going on on screen at once. It’s important to track how many meters you have, denoted by a number next to your meter. Meter is used to perform super and hyper combos.
Skullgirls: Most stylistically similar to UMvC3 than anything else I’ll talk about. Technically it’s more similar to MvC2, but that’s not played competitively very often/widely. Chain heavy combo system. Meter is handled similarly to UMvC3. However, you can pick the size of your team, 1, 2 or 3 members.
Others that I feel I can’t say much about: I don’t know much about other airdashers like guilty gear, but I’m sure that one in particular will get a lot of play in tournaments for a long time. KOF13 has long combos and a somewhat-difficult-to-grasp movement system with many different kinds of jumps. I know absolutely nothing about killer instinct.