well, we all know it. You check your list in PVP and certain characters/team combinations are a simple "no thanks" that will bei avoided.
For me it mostly are the newer characters. Once they were new, the valkyres were avoided by me, later the liliths and then some of the gods.
At one time even VH and Wrath were a deadly defense.
By now i clearly avoid the following characters: (exceptions may occur)
Osiris (my primordials are an easy prey for him)
Redan (that damn high healing)
Musashi
Prime Killer
the shinobis (sometimes i take on the magus one, but the others i avoid)
the count
the derby demons (i know the red, blue and green are a beast cause i have them... haven't seen the assassin one much yet)
assassin hellraiser once was on that list, but since they changed his eclipse-passive to counter, i'm fine with him as enemy.
I'd add charlotte to that list, because - rightly equipped - say with echo - she's a killer.
Some cases with Prisoners, Cyborgs, Navigators, Gunner NBOL, child or rockets or others, who can equip the primordials - it's rather a roulette depending on the rest of the team.
Sure in some cases a simple looking team can kill you instant because of some talismans (eternals, for example), but that's 1 out of 10.
What are your pvp boogeymen?