Big movie studio B movies not B enough for you?
Well, check out this list of Poverty Row pictures.
Monogram Pictures (Sono Art-World Wide Pictures & Allied Pictures merged)
Producers Releasing Corporation (PRC)
James Cruze Productions
Paul Malvern Productions
Larry Darmour Productions
Grand National Pictures
George A Hirlman Productions
Jack Broder Productions
Supreme Pictures Corporation
Columbia Pictures was initially a Poverty Row studio called CBC Productions until it reorganised in 1924.
MGM purchased Tiffany Productions's nitrate original film negative library and burned it in Gone with the Wind's Atlanta burning scene.
Republic Pictures garnered A list directors and larger budgets by the mid-1940s, including John Ford and Frank Borzage. (all its pictures within the Golden Age of Hollywood are included here)
An accompaniment list to The Big Five and the Little Three