I was just at the Aero Crew Solutions job fair at DFW last week. Many pilots were there for Spirit airlines. I think there were only 25 pilots who were there specifically for the Regionals. Here's a list of Regional companies who attended to try a get those mere 25 candidates.
Horizon
PSA
GoJet
SkyWest
Cape Air
Piedmont
Compass
Endeavor
Envoy
Trans States
Ameriflight
Allegiant
And a few more I can't remember.