At present, we have the following "lens mounts" in the mirrorless arena:
- Fujifilm: X mount (also called XF)
- Leica: M-mount
- Nikon: CX Mount (also called 1-Nikkor, or Nikon 1)
- Olympus: m4/3 (micro 4/3)
- Panasonic: m4/3 (micro 4/3)
- Pentax: Q Mount, K Mount
- Ricoh: GXR lens/sensor modules (S and P are small sensor, A is APS sensor)
- Samsung: NX Mount
- Sony: E-mount (NEX)
Third party lens makers have announced support for some of the mounts, as follows:
- Fujifilm XF mount: Zeiss
- M-mount: Cosina (Voigtlander), Zeiss
- m4/3: Cosina (Voigtlander), Kenko, Komamura, Samyang, Schneider, Sigma, SLR Magic, Tamron, Tokina, Yasuhara, and Zeiss
- E-Mount (NEX): Cosina (Voigtlander), Samyang, Sigma, Tamron, Tokina, Yasuhara, and Zeiss
- NX Mount: Samyang
- Nikon 1 (CX) Mount: None
If you're interested in my recommended m4/3 lens list, you can find it as a B&H wish list of m4/3 lenses here.