Well, the
amiga.org archives would be a good start I guess.
I've got a load of old Amiga Format CDs here which I know have website mirrors on them, but I'm not sure exactly what is covered. I know some contain mp3s of Jim Collas' speeches. I almost certainly have some interesting stuff on back-ups of my A1200's hard drive (backups go back to 1998), but they are in a bit of disorganisation. I'd have to look through to see exactly what I've got.
I also have a load of Amiga Magazines. I've got the Amiga Computiong "auction special" which covers the auctioning off of Commodore's assets in excrutiating detail, but no way to scan it in unfortunately.
I'll post back when I've had a chance to see if I have anything that might interest you.