Dragon Ball loves its transformations. From Super Saiyan to the various different forms that the villains take, there is a long history of transformations in the series for fans to count on. It is also common for these many forms to have many different versions to choose from. The characters often have a lot of different ways to express their gains in power throughout the course of the series. Gohan has his change into Super Saiyan 2, Piccolo's fusions with other Namekians and his Orange form are definitive for him, and Goten and Trunks have Gotenks' Super Saiyan 3 form to fall back on. The best example of this particular phenomenon is, of course, the main character, Goku.
Source：https://www.cbr.com/dragon-ball-every-ultra-instinct-goku-explained/
