I tend to favor supporting roles in team games, so I'm usually either a tank or support. Reinhardt and DVA are my go-to tank heroes, while Mercy and Lucio are my go-to supports (been enjoying Zen quite a bit though more recently).
Heroes I can play (in no particular order): Reaper (even before the buff), Soldier: 76, Bastion, Junkrat, Mei, Torbjorn, D.Va, Reinhardt, Roadhog, Winston, Ana, Mercy, Symmetra, and Zenyatta. I do tend to play Tank and Healer more than anything else, but I am a Flex Player so I can do a bit of everything.
Heroes I'm useless at: Lucio (the old was I was good, the new one I'm hopeless), Genji (can't get used to the movement), McCree (can't hit headshots enough to justify playing him), Pharah (cause I suck at predicting movement), Sombra (working on it), Tracer (can't aim that close to heroes lol), Hanzo (more prediction shooting), Widowmaker (in every other game I'm a good sniper, except in overwatch where I don't hit shit), Orisa (cause it's Orisa), and Zarya (too much passive play with the shields).
Bit of a bump but I started out with D.Va as I hadn't played FPS in a long time and a tank that was really forgiving and easy to aim with was a great start. Once she got buffed I found I couldn't get her much so I moved onto Pharah who saw not too much play then. I immediately fell in love with the shooting style, it reminded me of old halo days where you would lead your shots with the pistol or sniper. I always struggled to land headshots with regular weapons but leading shots felt fantastic again. That lead me to try Ana who felt really similar and the pair are my top two now. I cant land any shots with McCree or Soldier as I always shoot just in front of the enemy and just gave up trying. FInally, Mercy comes in at 3rd who I just like as I get to always feel like my gameplay matters when the game is going on.
Most of the time, I'm playing support. And when I'm playing support, it's usually Ana. I also play a lot of Lucio and Zenyatta, depending on the match type or enemy composition, but its time to hit up and try hard, I'm usually Ana. Shes probably my favorite character just cause I like her design and how she plays. I'm useful as a healer but I can help if were focusing someone. I like to play a lot of different characters, but most of the time, no one wants to heal, or they do something like play Zen as DPS and don't heal.
I also like to play Zarya, Roadhog, Pharah, Tracer, Junkrat, and Widowmaker. If I'm just messing around in QP, I will pick last and just fill.