The success of the Star Wars "Galactic Heroes" led to the line expanding to include other Hasbro licences such as Transformers, Indiana Jones and Marvel comics. Fans, like myself, really liked the chibi-esque deformations to beloved characters.
Other toy developers have followed this trend to varying degrees of success. UK company Character Group have done a great job with these Doctor Who Time Squad figures. The line is companion free, populated by adversaries of the Doctor, and one David Tennant Doctor. The product is still very new so I can't wait to see what they do with the later waves.