I use it often enough to donate to it yearly. The first thing that comes up when thinking about what would be my favorite is a whole rabbit hole on Japanese equivalents of RSS feeds that came out in the same period as the first versions of RSS. I translated the documentations I found via the Wayback Machine for Hina-Di and LIRS, two formats I found. But there are so many other things. I grab old Windows updates, obsolete utilities, PSP games, cool icons, ISO standards that would otherwise cost hundreds, and occasionally read books to get some technical documentation… or magic.