I'm glad to say that I possess a copy of the Other Edens anthology, edited by Christopher Evans and Robert Holdstock, which has been autographed by the cover artist and all but two of the authors.
The authors are, in order of inclusion in the contents, Tanith Lee, Christopher Evans, M. John Harrison, Ian Watson, Brian Aldiss, Graham Charnock, Robert Holdstock, Michael Moorcock, Garry Kilworth, R. M. Lamming, David S. Garnett, David Langford, Keith Roberts, and Lisa Tuttle, and the cover art is by Jim Burns. It's pretty clear that Burns' signature is on the inside front cover, and the title page has been signed by twelve people. Most of the signatures are more or less clear enough for me to read them; two I am not sure of (though I think they are Robert Holdstock and Tanith Lee), and that means there must be two authors missing (probably Ian Watson and Keith Roberts).
Tanith Lee?
Robert Holdstock?
I guess that some of you may have books signed by the doubtful or missing authors; please enlighten me!