It'd require some effort to come up with some gamemodes on the first try through.
The first thing I'd recommend I suppose would be a mix of TTT and Hidden in TF2; Turn off player cap per team on vanilla, have everyone but one go on the blue team, make that one person go spy, and backstab, disguise, and cloak, possibly with having a spectator teleporting players at random to different places on the map to screw with them.
If you could set up some melee fights in a giant box, that'd probably work, too, if you can enable FFA or friendlyfire, even better.
I feel like deathrun maps might be a thing on TF2? I can imagine maps where you're supposed to be scout and jump around to reach the top/end/bottom of the map.
Just a couple ideas to throw your way.
