Here's the UK Version of it that i know from memory; (Pictures are from Tony Clayton's Website)
The Gillick Obverse (1953-1967) (also including a proof only issued of predecimal coins issued in 1970 to be sold as 'the last predecimal' coin sets.) This obverse is still in use on the Maundy Money produced in the UK as handed out by the Queen.

The Machin Obverse (1968-1984) Now only used on stamps.

The Maklouf Obverse (1985-1997) No longer in use.

The Rank Broadley Obverse (1998-present) Used on all new coins except the Maundy Money which retains the orginal 1953 design.

Are there any countries still out there that still issue new coins bearing the Machin or Maklouf obverses? I believe some countries skipped the Maklouf altogether. Whilst others such as Canada came up with their own...