Oh, and Greg, Joan Collins also did both ST and Batman, appearing as the Siren in the third season of the latter. Other actors who did both include Roger C. Carmel, Stanley Adams, Malachi Throne, Grace Lee Whitney, John Crawford, Leslie Parrish, Nancy Kovack, and more.
I figured Trek
shared a few more guest-stars in common, but thought that Gorshin and Newmar and Craig were the most notable examples.
Vincent Price did an episode of F Troop
back in those days. Can you imagine him on Trek? Or maybe Karloff and Peter Lorre?
(Karloff did U.N.C.L.E.
and Route 66,
as I recall, the latter with Lorre and Lon Chaney Jr. as well.)