I also want to put in my dark horse vote for Riverside. Lotta badness going on on that label.
I had this Charlie Byrd lp. I think it was on Riverside, or a subsidiary.
Looked mint but there was a terrible hiss throughout the album.
I was half way through the second side before I realized the hiss was the drummers non-stop brushes.
The first thing I think of when I think Riverside is The Sounds Of Fast Cars!
When I see these label discographies, it's cool seeing the stuff you wouldn't expect.
Blue Note pretty much stayed true to the jazz vision and only started doing non-jazz in the past five years or so (Al Green, Amos Lee).
Impulse, as you can see from the book, made a few detours into folk and comedy. (And the first Genesis LP, as somebody stated earlier.)
I have an old Prestige catalog from maybe '64, and it looked like they were kicking as much butt with world music and folk/bluegrass as they were jazz and blues.
But Riverside took the cake. Besides Theolonius Monk and Cannonball Adderley, they also had sound effects records, dipped a toe in the folk/bluegrass scene, got right with God on some gospel elpees, and even had a subsidiary label for children's music (Wonderland).
And when they briefly revived themselves in the mid-sixties, seems like their big artist was soul singer Lou Courtney.