You're all familiar with standard puzzles on lichess. There is also the chessvariants website where you can do zh puzzles. But I have created several play against computer studies so you can do zh puzzles on lichess directly. I will make more in future. Here is the link where you can read more and see some videos of me trying to solve some of the puzzles. http://zhchess.blogspot.com/2018/10/crazyhouse-puzzles-on-lichess.html
If you are interested in crazyhouse, do please subscribe to my YouTube. I do also post normal chess stuff sometimes, but it's mainly crazyhouse commentary and hopefully instructive videos to get better at zh.