LogFAQs > #979496349

It's definitely not Gen IV (almost nothing except a baby and an evolution of something from Gen II), Gen V (the only Fairy is a less-than-great line), and Gen VI (holy hell for the generation that introduced Fairy-types, Sylveon is the only truly GOOD Pokemon on that roster). Gen VIII & Gen IX have some good stuff, but they also have some trash. Gen III has two stars, but also a worthless baby and Ralts. Similarly, three of Gen II's are babies, and Snubbull isn't THAT great either. So it comes down to Gen I (which I think is almost perfect except Wigglytuff is kinda lame) and Gen VII (which has more duds...but also a much larger roster.)

I've gotta go with Gen VII, because A-Ninetales, Primarina, Cutiefly, Ribombee, Mimikyu, and the Tapus are SUCH high quality, and Morelull/Shiinotic are good choices for Grass/Fairy.