Star Trek for sure, with GoT and Spider-Man right behind. Star Wars has shots that are a bit tighter, so harder to get in the flow, but it's definitely there if you can hit them. ST and GoT are much more forgiving making the flow easier. SM has great flow, but stops the ball a bit more often with the locks, Oct, Sandman. Can't go wrong with any of these four if you like flow though.

Also, it wouldn't be a popular opinion, but Avengers has some great flow if you can hit the tight shots. When you are on, you can do some crazy flowing combos on an LE with the controllable crossover ramp diverter. I once hit Cap to Hawkeye (cross left) to Widow to IM and into Hulk. All five Avengers in one combo. It felt great. Of course with how tight all those shots are that isn't something that happens often. Just looping BW a few times feels pretty awesome though. I do still miss that game sometimes...wish I could keep them all!