All of them. He doesn't even need to try to kill them, only in Spacebattles will people even entertain the idea when no one in JJK will be able to defeat a Servant, let alone EMIYA.
He's too damn resourceful, clever and not the type to jump into shit not ready to bounce if he needs to unless it's explicitly to save someone, all of the worst traits to put him against anyone there even if they are somehow Servant-tier.
Defeating a person that's capable of taking hits from freaking Passionlip and is only out for a second before a full recovery? The man who survived getting hit by Rhongomyniad, which even if The Lion King didn't use all of it's power, was explicitly trying to kill him? Neither of those was with Numerals of The Saint mind you so the obvious answer is... yes, if Emiya is leagues above JJK, then Gawain is a league above EMIYA even without Numerals.
Strong Cleave is not instantaneous and not something Sukuna can just do(Which I constantly had a feeling that was the case) and considering EMIYA has both Hawkeye AND Mind of The Eye, he would not only see Sukuna doing something different, but also KNOW what Sukuna will throw out is dangerous...
But again let's be real, Servants have taken much, MUCH worse damage than Strong Cleave, it would just be an annoyance at best.