In March 2018, I lost access to the Tumblr account that hosts these themes. Not really a loss since I haven't been using Tumblr for many years. So far as this repository is concerned, I've lost access to all assets stored on Tumblr, and can't access the blogs associated with them anymore.
I'm hesitant to invest a great deal of time into rebuilding the lost infrastructure. My work these days is in WordPress and other more modern tech almost exclusively.
The Win98 theme I made, based on Windows 98, still works fine despite losing my Tumblr account. It can be installed on my themes website linked above.
This repository is archival.