Bobbs-Merrill Black Bat line
I should have noted the depth of the Black Bat line last night. I tried to find the name of the editor on line today but had no luck so I'm doing this from memory. (I've mentioned Jack Bickham and Gregory MacDonald).
Bill Pronzini did three or four Black Bat titles, including two of my favorites of his, The Jade Figure and the really exciting and mordant Dead Run.
Dean Koontz under his Brian Coffey name did three Richard Stark variations that are terrific thrillers.
And Charles Alverson, who had a promising career as a p.i writer, started as a Black Bat writer with a very sophisticated first book.
I'm sure if I could ever find the entire Black Bat bibliography I'd find many more