I think it would be really nice to have, an option to favorite any puzzle, and have a separate tab that list all of the “favorite” or “starred” puzzles. I think it would be helpful in finding puzzles again, or if you’re working through a particular set. for example you want to reference a joseki puzzle you can easily find it again to continue working on learning them, or if you find a really good one and later you want to recommend it to someone, it can easily be retrieved.
I know there have been posts about this some time ago but all of them have fizzled out, it would be cool to get this implemented!