List of brands that produced cameras that can be used with a lens with an M39 thread (Leica thread):
Leica: Leica M-system cameras such as Leica M2, M3, M6 and others use lenses with M39 thread.
Voigtländer: Some Voigtländer camera models, such as the Bessa R and Bessa L, are also compatible with M39 lenses.
Minolta: Some Minolta cameras, such as the Minolta CLE, have an M39 thread and can accept suitable lenses.
Canon: A number of Canon cameras, such as Canon IV, Canon VT, Canon P, also use lenses with M39 thread.
Nikon: Several Nikon models, such as Nikon S and Nikon SP, have the ability to use lenses with M39 threads.
Contax / Zeiss Ikon: Some Contax and Zeiss Ikon camera models are also compatible with M39 lenses.
Ricoh: The Ricoh 500G and 500GX cameras also use lenses with M39 threads.
Konica: Some older Konica models, such as the Konica III and Konica IIIA, can also accept lenses with M39 threads
And also many other cameras