LogFAQs > #986602288

The Mush Badges in Superstar Saga add damage based on how many Mushroom Healing items you have. You can mix this with the Great Force accessory that doubles all damage you deal to achieve ludicrous amounts of damage. By the time you get them it's perfectly feasible to dump all your coins into Mushrooms and steamroll the game by 1 or 2 shotting every enemy.

Pokemon singles has a ton of broken stuff but one of the most interesting is probably Arena Trap. Arena Trap prevents the opponent from switching and has allowed Dugtrio to act as a targeted assassin to completely break games open. It's so strong that even after Dugtrio was banned, people used Diglett to accomplish similar tasks, so much so that the ability itself was banned from every generation except Gen 3, where a significantly lower power level allows to Arena Trap to be extremely centralising but not quite bannable broken.