Basically :?
QF Mod requires it to work. It is the only full-scale mod released post pb4a.
Mini-patches are being made for others like Fleshstorm and Forgotten Enemies.
SRV will soon (I hope :P)
MRVP 1.0
still working on the improved and bug fixed 2.0
Fleshstorm already has a mini-patch. FE still doesn't work properly, but Uler does (so long as you want to play IA)
Fleshstorm has numerous bugs however. It DOES work in pb4a, but ive tested it and a lot still needs to be done. I think Commando was doing it but no doubt hes too busy with RL or the private betas.
I COULD fix it, but it would mean taking time out of modding S'nesis, which i barely get time to do as it is. Ive posted the bugs i spotted on BZ2MD though, maybe someone else can take up the challenge.
The most noticeable issue with bringing mods from PB3 into PB4a is the physics problems. Physics code has again had a change, and most units be have like they are driving on slippery ice. It did make my little jeep drive really well though, can get some mint powerslides out of it =].
But yeh atm i think these are the only ones ^. Many are planned however.