Thirsty Ear (US) & Hannibal (Europe) have released (release date February 9th) a 5 CD box with unreleased tracks, EPs, singles & ditties. Here's what I could find out:
Both singles from 1974-1975 plus the Calyx track (1974?) from the Going Back A Bit 2CD compilation.
1982 single tracks (Shipbuilding, Memories of You, Round Midnight), Pigs (1986), Chairman Mao (1984) from two compilations. Enhanced CD track: Shipbuilding videoclip.
Work in Progress EP (1984).
The Animals Film EP (1981).
Jungle (!) remixes of tracks from Shleep (1998).
Or go to the Soft Machine index