I originally had this in the top 10 actually, but swapped it out last minute because the game I originally at at 11th going out here just felt wrong.
Pokemon: Too Many Types is so incredibly fun. There's not much to say on this one, though. Instead of the usual 18 types, now there's 62, and Pokemon can have 3 types instead of just 2, so the type chart is fucking brutal.
Other than that, it's basically just Emerald again, but like with a lot more types. It's a really hard game, especially the champion's team, and there are also a few FUN surprises I don't wanna spoil because it just gets fucking wild at points.
Not much to say here! Just a really great rom hack that I almost put in the top 10 over one of my favorite indie games of the year, and I can not recommend enough if you enjoy Pokemon.