Prepare for DOOM!

To sum things up, this is basically a highlander-esque team meant for pubs.
I would have a bunch of friends play a specific role- mostly revolving around the heavy or medic's rampage- and basically create a Donald Trump's wall on wheels, with more (or less) pain, death, and destruction.

Originally, our team build up would be this:
One player: Heavy
Two Players: introduces medic
Three Players: introduces an explosive class for crazy damage
Four Players: pyro comes in to protect and support
Five Players: at this point anything that'll add damage or longevity to the team is cool