There's the archived ones that were moved out of their section (GTs and such mostly) here. There are also some that are old archives of sections that were disabled/remade, like Webmaster Discussion, Member Fanclubs, DPPt, HGSS, and S&M. I think I got them all!
Edit: It seems like only some of these are viewable from the actual forum number. The rest seem to be hidden for staff only. Sorry!