Stryper is a Christian metal band that formed in 1983 and is still going strong today. They've just released their latest studio effort, Even the Devil Believes, and it's already charted very well. During a hiatus the band took in the 90s, frontman Michael Sweet started a solo career, which is something he's continued even since the band's return, juggling that, the band, and other projects. He also formed Sweet & Lynch with George Lynch of Dokken fame.
Since the 2010s he's been so active fans haven't had to wait more than a year between most of his projects.
I've also included in this list SinDizzy's only album, a band that two Stryper members Oz Fox and Timothy Gaines formed during Stryper's hiatus, as well as Timothy Gaine's solo album.
As of 2016 Gaines is no longer with the band and bassist Perry Richardson from Firehouse has replaced him.