Blue Oyster Cult
BOC never really sold out and that is why they never reached the kind of commercial success they should have achieved. Everyone knows "(Don't Fear) The Reaper" as it is blasted at us every Halloween. But the song is worthy of listening any day of the year and limiting the track to one scary special day does a disservice to the tune and to the band. Blue Oyster Cult were hard rock and pro rock masters.
They had other great songs, of course. "Burnin' for You" still gets some airplay. So does "Godzilla." But the depth of their albums is undervalued by the general public but not by other bands that matter. Alice in Chains and Metallica were both influenced by BOC. Ghost sometimes sounds like a Blue Oyster Cult cover band and that is not meant as a slight.
Chic
On the opposite side of the spectrum from BOC is Chic. While disco can be a divisive genre of, well...something, this group actually produced some songs that would hold up past disco's sell-by date. "Le Freak" is somehow catchy after 50 years, though you still might not want to tell your friends and family you are a fan. Disco is a bit taboo, but Chic should not be.
Other musicians who are fans include Elton John. As recently as 2018, John and Chic collaborated on the group's album, It's About Time. Oh, and Lady Gaga collaborated as well. Plus, Niles Rodgers is part of the band and he has been an important producer, such as on David Bowie's Let's Dance album, and musician since the 1970s.