Plates tend to bear the State or Territory name and perhaps a state motto or slogan at the top and/or bottom of the plate. Recent issues of plates (since the 1990s) also often use the state’s colours and may include some imagery related to the state (such as the state’s logo as the dot separating the groups of numbers).
Vehicles running on autogas or compressed natural gas must have a metal diamond with a white lettering LPG on a retro-reflective red background or metal disc with white lettering CNG on red background. The tag must be mechanically fixed (and is usually riveted) onto both of the registration plates. If multiple gas tanks are fitted to vehicle, multiple tags are required – one tag for each tank installed. Subsequently, vehicle manufacturers who manufacture cars with LPG as standard fitting, provide LPG stickers already stuck to the vehicle’s registration plate areas, and some state and territory registration authorities also are producing plastic “flat” printed registration plates, and therefore need to provide LPG stickers to avoid damage to the plates if drilled for pop rivets.
All hybrid electric vehicles must have a green diamond sticker with the word “Hybrid” written in white letters. This became a mandatory requirement on all hybrid vehicles registered in Victoria from 1 April 2009, and is designed to warn emergency services in the case of an accident that the vehicle contains high voltage cabling throughout the vehicle. If you wish to get additional info, then you can check this California license plate lookup tool for more details.