Apart from the film itself, I have what's in the UK Imperial Edition, namely:
- A few surviving pieces of Tinto's workprint
- Some of the "Bonus Footage"
- Several "rushes" of some scenes
- A few deleted scenes from the Making Of documentary
- Behind the scenes footage, possibly
The "Io, Caligola" DVD and the Unreleased Guccione Cut should have more detail, but I have access to neither.