Super saiyan 2 is the strongest transformation that was in the cell games. it is a 100x boost from your normal state and a 2x boost from super saiyan. it can be achived by sadness anger regret, and training for it
Super saiyan three is going even further beyond. HAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAARRRARAAAAAAAAAAGRRRHHAARRREEEEGRAAAAAAAAAHHHHURRRRAAAAAAAAAAAA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!. it is a 400x boost. it can be achived by training and yelling at the top of your lungs for 5 mintues and 37 seconds
super saiyan four is achived after a golden ape form. it has an unknown strength boost