What teams do the TF2 mercs belong to?

I didn’t think I’d need to mention this, but if you have something to say about me being left handed, you’ll be banned. Have a nice day. 0:00 Intro 1:00 Engi 1:25 Spy 1:56 Sniper 2:35 Pyro 3:10 Scout 3:51 Medic 4:34 Demo 5:40 Heavy