Here's my list of DA20 On Demand Cargo operators...let me know if I've missed any...

Cherry Air (KADS and KTOL)
Ameristar (KYIP, KELP, and KADS)
Royal Air (KPTK, KMWO, and KELP)
IFL (KMFE and KPTK)
Sierra West (KELP)
Kalitta (KMOR and KYIP)
Alliance Air Charter (KDTO and KYIP)