Single-8
Single-8 is a film format introduced by Fujifilm of Japan as an alternative to the Kodak Super 8 format. As an 8mm-wide cartidge-loading amateur motion picture film, the concept and the film itself is quite similar (Single-8 uses thinner but stronger polyester-based stock), but the cartridges were entirely different (Single-8 cartridges allow unlimited rewind, whereas Super-8 rewind was limited to several seconds).
Although never as popular as Super 8, the format continued to live in parallel.