Just this

[Venomkilled]

Played a round with almost everyone as medic and won, more than half the other team ragequit after that

 

[Nix]

Single-class teams are surprisingly effective. Especially medic chains.

I've won an all-pyro, an all-sniper, and an all-spy round before.

 

[Orange [INACTIVE]]

Medic is best class. All hail the Medic.