Also, to answer the question, probably Hungry Hungry Ogres. Great group of folks, including boon despite some of his personal issues spilling in-game or whatever. Rigel, rooks, and pun back then still go down as some of the most level-headed people I've ever played with while having good skill and potential. The only players I've played with that rivaled them in attitude are probably linkuser and boomer, though they only ever composed a sixth of a team during separate seasons.
I think every other season of TF2 I played was marred in some way or another. clam bake was a sandbag team that I actually have no recollection of aside from a terrible grand finals involving disconnects, -bird noises- for all three seasons I played was pretty good but somehow always devolved into a blame game where we ousted some player or another with some good reasons but often a lot of passive aggressiveness since everyone but linkuser, boomer, and indust (yes, myself as well) were massive bitches who always spoke behind people's backs or somehow fucked up team chemistry before there was even a chance (matt after S20, hellbent after S21, everyone but corsa after S22 I think). Ironically, I guess people like hellbent blame me for this simply because I happened to be the one that told him he was cut (for example) despite numerous other teammates pushing for the same thing while actually being painfully NOT objective about it (e.g. I don't like hellbent since he's loud in mumble, can you guess who said that?) Sucks to be the vocal "leader" I guess
Regardless, it's very true I failed fundamentally as a "leader" on that team and the remaining seasons I played I half-assed and slowly convinced people to either kill the team I was on or contribute to its premeditated death because someone or another went to join another invite team. Hungry Hungry Ogres <3.