Bally Solid state games:
SBM- ripping the horseshoe from the left flipper and then catching with the right flipper. Nail it again with the right flipper and catch with the left. Repeat again and again.
Xenon- Rip the tube shot with the right flipper.
FG- pretty much anything that doesn't cause a drain.
Paragon & Centaur- completing the inline drops- really tough