The first test card "Tuning Signals" was broadcast by the BBC in 1934. It was a simple line and circle broadcast using Baird's 30 line system, and was used to synchronise the mechanical scanning system.
Test Card A made its debut in the late 1940s. However, it and Test Card B were soon replaced by the more useful Test Card C.
Test Card B was an early BBC television test card. It was very similar to Test Card A but was never broadcast. The original card has since gone missing. Test Card B was very similar to Test Card A. The only difference was it had an extra greyscale stripe below the circle. The letter box in Test Card A was moved to the top of the card. This card was never broadcast, possibly used for by BBC engineers for internal use. Below is a reconstruction of Test Card B using a studio picture of a partial Test Card B.
Test Card E (shown on left) was a television test card designed in 1964 and made to accommodate the 625-line system on BBC2, as opposed to the 405-line system of Test Card D. However, it only lasted one day on television, and was soon replaced by a modified version of Test Card C (shown on right). This lasted until 1967 when the colour Test Card F was introduced.
Test Card H abandoned in development - it was never broadcast. The "H" designation was also used for a studio line-up card, so it was not allocated to a Test Card to avoid ambiguity.
The High Definition version of Test Card W is visually similar but lacks a designation letter. This version is often referred to as Test Card X, but this is not a designation which the BBC recognises. It is designed for use on High Definition TV services, and has been included a part of BBC HD's preview loop since November 2008 (though has been in use internally at the BBC since several years earlier).
An electronically generated image was first broadcast on 21 June 1997 on BBC2 between 3am and 4am. The test card was then seen again 17 April 2007 between 4am - 5am during the BBC Learning Zone both transmissions were accompanied by a 4-tone test tone, ranging from extremely low frequency to a very high shrill. It is unknown if this Test Card has a name.
There has been a number of Un-Transmitted Test Cards. They would most likely be for internal use inside the BBC. Most of them are adapted from Test Card F.
A Comic Relief Testcard was broadcast BBC1 on 18 March 1993 as part of Comic Relief.