Canon:
    FL - Introduced in 1964
    FD - Another mount (incompatible with FL) feat. automatic aperture
    EF - Another incompatible mount, EF stands for electro-focus
    EF-S - A newer variant of EF with shorter flange depth, allowing
           for manufacturing of less expensive wide-angle lenses. Not useable
           on cameras with crop 1.0 and on EF-only cameras.

Contax:
    N - ?
    Contax/Yashica - ?
    G - Rangefinder mount with autofocus

Generic:
    M42 - First used in Zeiss Contax S (1949) and then adopted by many
          other manufacturers due to patent-less nature.
    T2 - Introduced by Tamron in 1957, with adaptors for virtually all other
         mounts (due to large flange distance).  Used in astronomical
         devices and some mirror lenses.
    C - Intended for cinematographic lenses on very different viewframe sizes
        (often smaller that µFT), it can be adapted to most mirrorless systems.
        It has a very short flange distance, but due to the small radius of
        most C mount lenses, the adapter can be realised as a ring around the
        lens.  In photography, most C mount lenses must be considered fun
        lenses.

Leica:
    M - Classical Leica rangefinder mount
    R - SLR mount, discontinued since 2009
    S - Medium-format mount

Hasselblad:
    H - Current medium format mount of this brand

Minolta:
    MC - Older Minolta mount for manual lenses
    MD - Newer version of MC with aperture information to the camera
    AF - (1985) features autofocus, several generations.

Nikon:
    F - Introduced in 1959
    F AI - (1977) - Added electrical interface for automatic aperture control.
    F AI-S - (1979) - Added a mean to tell camera current focal length.
    F AF - (1986) - Added screwdriver AF coupling, compatible with older mounts

Olympus:
    4/3 System - (2002), the new "digital" mount together with Kodak

Pentax:
    K - the original mount as introduced in 1975
    KF - the world's first autofocus mount, 1981. Abandoned.
    KA - the K mount plus electrical contacts to detect the min/max lens
         aperture and also whether the 'A' aperture mode is enabled.
    KAF - the KA mount plus autofocus
    KAF2 - in addition to KAF features implements power zooming and
           adds MTF information to the lens data

Samsung:
    NX - mirrorless APS-C mount introduced in 2010
    NX mini - mirrorless 1" mount introduced in 2014

Voigtländer:
    DKL - the "Deckel" mount used in the Bessamatic