Infinity Watch vs JLA, JSA & Teen Titans
The Infinity Watch almost took out the combined Avengers, FF, Alpha Flight & X-Men in Infinity Wars before Galactus stopped the fight.
How would this one go?
Stipulation: The Watch can use the Infinity Gems but cannot combine it to make the Gauntlet. Thanos can't use the Reality Gem but he has his chair.
Not sure, but I'll go with the Infinity Watch. Warlock can trap them in his soul world and kick all their asses. Gamora can freeze the other teams in time and give Warlock and Thanos prep time to figure out a way to win. Or Thanos takes Drax's power gem and boost him to even a higher unimaginable level then preceeds to beat the other time to death.
Or maybe you can do us all a favor and list who's on the JLA, JSA & Teen Titans that the IW have to fight.