Most of the ones I’d thought of already appear, here’s a few others (apologies if they’ve already been done):
Jefferson Airship / Jefferson Starship / Starship
Early (punk guitars) Tubeway Army to late Tubeway Army / Gary Numan solo
Adam and the Ants in a couple of directions – Adam went from punk (having started as a pub rocker) to “new romantic” while the Ants went from being Ants to being Bow Wow Wow with the addition of their singer. (meanwhile Adam recruited a new set of Ants prior to pop domination).
Siouxsie Sioux and Budgie – both in “and the Banshees” and the Creatures – the latter was a completely different thing each and every time they rolled it out and the former progressed from goth/punk/rock (pick a pigeonhole to taste) and had their biggest hit with a dance themed single that also heavily featured an accordion.
Joy Division into New Order? Surely that’s been mentioned and I missed it? [EDIT: While I was typing!]
Genesis
Yes (thinking “owner of a lonely heart”)
Slade had tried a few different approaches before hitting gold with the glam rock thing
And of course, the band that started as a skiffle group, did some early rock’n’roll, had a big psychedelic hit before hitting the big time with that big, big metal sound: Spinal Tap!
If you take their first and last albums, you can see a fair old change in them there Beatles over only what? 6 – 7 years?
Manic Street Preachers? Or is that just called “growing up?”
Deep Purple: Similar to the Quo, first known for a big psychedelicish hit (Hush) before world domination in a different way.
The Yardbirds via a slightly meandering route into Led Zeppelin