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?
I think that depends on what you consider an arc. I would consider the entire time they’re on namek the frieza saga