For the original run of d6 RPGs that were developed and published mainly by West End Games, see D6 System (WEG).
West End Games developed the original D6 System (WEG) in 1986 and it was used in various games. But the company finally went bankrupt in 1998, and was purchased by another company. Eventually the assets were owned by Humanoids Publishing who, in late 2003, sold the rights to the d6 System to Purgatory Publishing, Inc..
At this point the system was reworked and launched in a new format, with a set of basic RPGs released for the main target genres. The system was opened up for third-party developments under the name OpenD6, and now various new games have been created using this revamp of the D6 System.