Some of you may already know about this site, but in the interest of sharing....
I stumbled across this while looking up an older HPC device:
http://old-organizers.com/
There are a few HPCs, but it's mostly other types of organizers and handhelds. Most are from the 90s, with some from the 80s and some from the early 2000s. For those who like older devices, it's a fun stroll down memory lane.