The original Trixionary was built by Thomas Gossman as part of his PhD, and showcased how each trick is related to each other, and how they are built upon similar skills. Unfortunately, the original database of his work was lost in a server upgrade some time ago, however the tool he created to build it is still available on Github, and could be updated and rebuilt someday.
Some years later, Noli Ergas built a similar concept in an open spreadsheet based on a desire to document the various flatland tricks, and how they are interrelated.
Noli’s Trickionary Google Spreadsheet can be found here
We also now have a visual representation of Noli’s Trickionary curtesy of Nakul Mohakar, and the Cal Poly Unicycle Club (CPUC).
Check out the Trickionary at unicycle.wiki
Note that unicycle.wiki is built using Obsidian, and the graph view is more powerful when using the app vs the web interface.