Just occurred to me that there might not be one
Saiyan saga has kaioken which isn't technically a form but may as well be Frieza saga has super Saiyan, cell saga has super Saiyan grades and super Saiyan 2, buu has super Saiyan 3, bog has god, then blue, blue evolved and ui
Am I missing one?
GT is pretty bad, not really done by Toriyama, and was written out as cannon. In the DB world it no longer exists.
That's a fair opinion to have since I believe even Toriyama said as much. However, in the end there is no such thing as a true canon - with the manga, anime and movies there are 3 different canons for Super alone. And personally speaking, they all suck just as much as GT did except for a few of the movies.