Here are five of the "Super" hacks seen on some early 90s multicarts - Super Donkey Kong 3, Super Galaxian, Super Pac-Man, Super Pooyan, and Super Star Soldier. These are pretty simple hacks conceptually; Super Pac-Man greatly increases Pac-Man's speed (similar to the arcade "speed-up chip" hack), while the other three just increase the player's bullet speed/power. Some multicarts also feature a "Super Star Force", though I haven't included it here for the simple reason that I can't figure out what it actually changes (outside of some nasty title screen coloring...)
Normally, these games are built into the original versions in code (i.e. unhacked Pac-Man runs on the same file as Super Pac-Man); I wasn't able to rip them for the longest time because of this. However, I came across a couple multicarts which run the "Super" games separately from the originals, allowing them to be extracted.