We all know that fans love to argue about what artists should, and should not, be in the Rock and Roll Hall of Fame. But another good argument that fans and artists have more and more frequently is: when a band is inducted, which members should be included? Gene Simmons and Paul Stanley of KISS, for example, were angry that only the original lineup was included in their induction, and not later members like Eric Singer, Tommy Thayer, and the late Eric Carr.

A couple of weeks ago, former Black Sabbath/Dio drummer Vinny Appice made headlines when he referred to the Rock and Roll Hall of Fame as “a bunch of f—in’ a–holes” for not including Dio with Sabbath. He has a point!

There are certainly lots of examples of bands who have had so much turnover that it definitely wouldn’t make sense to include everyone. Over 50 musicians have passed through Santana’s lineup. Chicago has had nearly 30 members over the years. Obviously, you have to be an excellent musician to step on stage or in the studio with those groups. But only a few of the members were truly important to the band’s peak era(s).

With that in mind, there are still some examples of musicians with vital roles in their respective bands’ histories, whether it was playing on classic material, or being a part of the band’s formation. We found more than a few examples of musicians that fit one or both of those descriptions but weren’t included in those bands’ inductions. Here’s hoping that the Rock Hall comes up with a new category to recognize these vital artists.