The first thing you need to do is define what you mean when you say "work."
- Fire in manual only mode with no higher level communication whatsoever between the camera and the flash?
- Mounted on the camera's hot shoe or via a wired connection?
- Be controlled in some type of TTL mode when mounted to the camera's hot shoe?
- Be fired wirelessly in manual only mode? Using optical or radio control?
- Be controlled wirelessly in manual only mode? Using optical or radio control?
- Be controlled wirelessly in some type of TTL mode? Using optical or radio control?
- Which specific model of flash "brand X?" (e.g. the Yongnuo Yn560/RF605/RF603 system, the Yongnuo YN622 system (Canon or Nikon?), or the Yongnuo RT clone?)
- Which specific model of camera brand Y (e.g. Sony/Minolta with ISO pin or Sony without ISO pin on the hot shoe?)
- How much trigger voltage can the specific camera model tolerate?
- How much trigger voltage does the specific model flash use?
The point is, there are way too many variable to make this a general question. The subtleties of each possible combination compared to what the user wants to be able to do make this a much more complex matrix than asking, "Will lens with mount X work on a camera with mountY?"