A little shame(less|ful) plug from me:
/t/WaniKani-at-Android-Speed/2300/1
Most of the conversation here has been focused on in-browser integration, so it’s not quite what you might be looking for.
It’s offline and therefore can’t update your WK progress, but it’s at least been a fun tool I’ve used myself.
Also:
/t/WaniKani-at-Terminal-Speed/1605/1 (After actually using the Android app so much, this terminal version is serious eyecancer)