“Sir” Roland Hanna (jazz pianist)

One of the post-war talented and versatile pianist, Roland Hanna is also cruelly ignored by the average John Doe jazz fan.
"Sir" not only featured with Mingus and many others, he also recorded a good 30 albums under his own name and/or formations, although never for major labels (hence he's now somewhat forgotten).

Casual jazz listeners as well as ignoramus hardbop fans may try the excellent Freedom release Perugia for a starter.