[cyclohexane]

This is what I know of the third party lens makers:

Tokina makes lenses with their name for Nikon, Canon, and some for Minolta. They don't make any more lenses for Pentax under the Tokina name because the Pentax equivalents are the same lens (12-24, 10-17, etc.).

Tamron makes lenses with their name for Nikon, Canon, Pentax, and Minolta. The Minolta thing surprises me because many of the Konica Minolta lenses are the same as the Tamron equivalents, compared to the two Tamron lenses in the Nikkor line-up. I don't know of any Tamron lenses in the Canon or Pentax line-ups.

Sigma does Nikon, Canon, Minolta, Pentax, and Olympus. Of course, they also make lenses for their own cameras.