vcscheatdevice.prx   GTA:VCS cheatdevice -
Doesn't even work in 3.10 OE-A

battery.prx   Shows remaining battery level and time on the battery icon -
If it's the one I use, it works.

scep.prx   a whole lot of stuff -
Has been updated for 3.40 OE-A

irsmp3.prx   mp3 playing -
IMHO, this NEVER worked for me except in the XMB. It's SUPPOSED to mute game sound, but it never did for me. Just played an MP3 alongside the game audio.

capture.prx   screen capture -
Works fine

antiupdate.prx  removes the UMD Update function thing -
Works fine

USBon.prx   access USB Mode anywhere in the XMB -
Never been lazy enough to need it.