The Avengers, vs X-Men, vs Justice League, vs Fantastic four, vs Suicide Squad, vs Sinister Six, vs The Brotherhood of Mutants. Who would win and in what order?
The levels of competion in this matchup are drastically different. The Sinister Six have had trouble corralling Spider-Man.
The Flash could solo all the teams on this list at the same time, minus maybe Thor and Colossusnaut (if he's still on the current X-men)
Ultimately, giving Flash partners such as Wonder Woman, Superman, Martian Manhunter and Green Lantern, and it's a complete decimation by them.
Justice League >>>>>>>>>> Avengers > X-men > Fantastic Four > Brotherhood (are you referring to Scott and Magneto's group?) > Sinister Six > Suicide Squad