Games usually not seen:
TOM (although the rom was recently hacked to avoid certain scoring exploits)
BOP
TOTAN
-Machines where you can steal multiball or other objectives from other players are used... However, they are usually played as single player games. A lot of system 11 games fall in to this category.
-Games where you can swap scores with other players.
Also, it is up to a tournament director whether to include a game or not include it. So, you will see games listed in this thread from time to time. There are just some games that can potentially create issues that most td's would rather avoid all together.