I can only think of two right off the top of my head:
-Van Halen. Wildly successful with David Lee Roth as the lead singer. Replaced with Sammy Hagar, and the band continued to be successful.
-Genesis. Peter Gabriel was the lead singer for the band, from its onset in 1967 until 1976. The band continued to enjoy popularity after he left and Phil Collins took over lead vocals.
I know other bands have tried it (Motley Crue with John Corabi instead of Vince Neil for one).
I’m not looking for bands that didn’t become popular/established until they replaced their original singer. Just bands that were already well-known before the replacing happened.
Are there any others that I can’t recall?