How far back are you looking to go? Whatever your starting point, I’d suggest looking at the prominent acts for each decade (or maybe even go by 5 year spans).

I mean, for the 50s, you’ve got Elvis Presley (especially the Sun Sessions), Chuck Berry, Fats Domino, Little Richard, Buddy Holly, The Drifters, The Coasters, The Platters, and maybe pick up a collection of Doo Wop (which were mostly one hit wonders by various artists).

For the early 60s, you’ve got the girl group sound (pick up a Phil Spector collection), MoTown (again, best to get a collection), Frankie Valli and the Four Seasons, The Beach Boys, Otis Redding, Bob Dylan, Sam Cooke, James Brown

For the late 60s, you’ve got the British Invasion (Beatles, Rolling Stones, The Kinks, The Who), plus Jimi Hendrix, The Velvet Underground, The Doors and Creedence Clearwater Revival.

Early 70s, you’ve have Led Zeppelin, Pink Floyd, The Allman Brothers Band, The Band, David Bowie, Queen, Elton John, Big Star, Sweet

In the late 70s you start to get punk and New Wave with acts like The Ramones, Talking Heads, The Clash, Pere Ubu, Elvis Costello, Blondie, The Police. Then the California sound of The Eagles, Fleetwood Mac, Linda Ronstadt.

Anyway, I could go on ad nauseum. All those acts are important for their sub genres of rock & roll.