There’s this thread where @jhendrix13 is working on one method Adding custom vocabulary to WaniKani
And this thread where I’m working on this
[UserScript] Integrated Custom SRS (don’t try using the userscript, it’s broken)
Both of these are very much WIP. I’m expecting to have an initial version ready by end of this week, early next week, and then I need to get it through the extension platforms requirements.