Pink Floyd - Rhapsody In Pink (1990) FLAC & MP3

This is the collection of material to hunt for if you're looking for unreleased Floyd from the post-Barrett, pre-Dark Side era.
Bootleg fidelity doesn't come any better than this; it's one of the very few occasions where you could argue that the sound may actually be better than most official releases.
These BBC airshots from the late '60s and early '70s focus on rather obscure material: "Julia Dream," "If," "Green Is the Colour," "Embryo," and the never-released "Murderistic Women" (a blueprint for "Careful With That Axe, Eugene").
There are also full-bore workouts of "Echoes" and "Atom Heart Mother Suite" that, depending on one's taste, could be argued to exceed the officially issued versions.