Four further books also exist. ISBN4-8401-0742-4 Avalon is a small book in Japanese, which as far as I can tell is either a retelling of the film's story, or closely related to it. Note that the illustrations are drawn rather than being pictures from the film.
ISBN4-87376-561-7 Avalon reportaz is a 'reportage' book around the making of the film. Text in Japanese with photos from the filming.
The other two titles are ISBN 4-8401-0156-6 Avalon Fanbook Realquest and ISBN 4-8401-0157-4 Avalon - both these are out of print. If you know anywhere that has them available please let me know - web at ninesisters dot org