Mattisse 1988-90 Paintbox system running on Cambridge based Spaceward Graphics Ltd. An early competitor of the more famous Quantel Paintbox which won a legal battle against them killing them in 1990. Quantel also sued Photoshop on similar grounds but lost the case later in '97.
Avid Media Illusion - One of the first high end node based compositing systems
Avid Matador - Great 2d animation package / paintbox RIP 1998
5D Cyborg - 2001 - very fast online compositing software to give Flame a run for its money- only lasted a year or two
Shake 1997-2006 - boo hoo - I'll have to go and learn Nuke