I like being support from time to time. I don't consider myself a good Mercy player, but she's pretty fun to play as, and it is very satisfying to bring an entire team back to life.
2. Soldier 76
It's like I'm playing Halo again. 76 seems to be the easiest to play as for me because he's so familiar. His abilities are pretty straightforward and he's really fun to play.
Although a bit difficult to get used to, to me she is a really nice tank hero. I like the story of pro-gamers making up Korea's military in Overwatch, and although her abilities take some practice to know when and where to use them best, they give pretty satisfying results when done correctly. Also, it's fun to eliminate people with her pistol after the mech is destroyed, and the fact that she streams her battles makes it even funnier.