Glad to see a thread for this!
Me and my Girlfriend play this game and we really enjoy it a lot. She mostly likes to play the healing characters like Luna Snow and Cloak & Dagger, which is great for me when we play together

I get the best heals ever and she pockets the hell out of me on Tank.
I mainly enjoy playing Venom. I like his style of diving in, causing chaos and trying to get a pick on one of the squishier characters. Sadly, he's not very good in the current Meta and gets destroyed by Emma Frost, she has a chokeslam thing which destroys you. When she's banned though or the comp works in his favour, I put on some pretty good games with him. His style of play is just so satisfying, you really can get up in people's faces.
When I'm not tanking, I enjoy playing Winter Soldier but I am so inconsistent with him. Either I pop off or I'm not hitting any shots at all. His kit is so fun though and he has one of the most badass ults if you can pull it off.