Hmmm...
I don't recall many either, under them would be his fights against Kenobi, Tano and Luke of course, and his fight against these Jedi Woman(Dark lady? Black Lady?) IIRC he also has beaten several Jedi shortly after RotS, has endaged(and won, I think) Galen in a Saber Fight, and has fought against Celeste Morne.
Just of the top off my hed, so some of them might be wrong tbh.
Surviving against the Jedi Enclave until stormtroopers arrived.
Duelings 4 or 5 Jedi simultaneously before TK'ing them.
Logically being more skilled then he was as Anakin.
Beating Muur empowered ( though not possessed ) Celeste Morne.
Stalemating and showing superiority as a lightsaber combatant to Starkiller.
Some of these feats I mentioned are before Vader's prime. Logically he would have grown as a lightsaber combatant after some of these feats and he's confirmed to have grown considerably in ESB and RotJ.