I'm going to try to avoid duplicating my faves that have already been mentioned. But these are just a few.
Often pigeon-holed as just a freak or more into juvenile humor than deserved. Absolutely underrated guitarist.
Frank has led me to numerous great musicians who've become favorites of mine, none moreso than Mike Keneally.
Very happy to call Mike a friend - as fabulous a musician as he is, he's a better person. And that's saying something, given what he's covered in his career, including (but not limited to) Steve Vai, Joe Satriani, Chickenfoot, Zappa, Dethklok, Screamin' Jay Hawkins, and more.
Through Mike, I met Bryan Beller.
Like Keneally, ferocious musician, with amazing organizational skills. It's not unusual for him to go from a Vai tour to an Aristocrats tour, to Dethklok, to Satriani.
Speaking of the Aristocrats.
And both of those guys led me to Dethklok and the inimitable Brendan Small.
Diverting back to the main Zappa branch, there's Steve Vai. Discovered him through Frank, then saw him with David Lee Roth live.
Zappa also led me to Adrian Belew. Another guy who can seemingly do anything - Bowie, the Bears, Talking Head, and a long solo career.
Zappa also led me to one of my all-time favorite drummers, Terry Bozzio.
Bozzio has played with a ton of people as well (that's him on Vai's "Still My Bleeding Heart" above), and he started Missing Persons with then-wife Dale Bozzio (who also appeared on a few Zappa albums).
All that from Frank Zappa. And there are more that have branched off from all of those, but I tried to stick to ones I'd consider more as favorites.
And that's WAY more than enough for one post!