If you like something insanely challenging, try Pokemon Clover as well. Though there are some elements that may deem offensive to some so be warned on the content. The Fakemon designs were pretty good, some are darn hilarious. It got super challenging to the point where you cannot use cheats at all (if you do, after beating the Pokemon League, your save file will be deleted) and the gyms and villainous teams on the postgame can be extra tough as well. The soundtracks are pretty lit especially the trainer battle theme in the Ebin region and Burial Tower.