>>57325084Clefable was dogshit in Gens 1 - 3. In Gen 4 it became great because most of the damage in Gen 4 is non-attack damage (Stealth Rocks, Spikes, Sand, Toxic, Burn) which Clef is immune to on top of having the pre-nerf Magic Guard that makes it immune to Paralysis. In Gen 5 it fell off again due to the Magic Guard nerf and the shift to hyper offense in the meta.
Then in Gen 6 it got Fairy type and never stopped being top tier. It's survived power creep that killed off:
>Heatran>Garchomp>Tyranitar>Salamence>Metagross>Hydreigon>Scizor>Weavile>Tornadus-T>Thundurus-T>Greninja>Excadrill>Mew>Rotom-Wash>Blaziken>Aegislash>Serperior>Skarmory>Slowking>Slowbro>Tangrowth>Toxapex>Jirachi>Manaphy>LatiosYeah, a Pokemon that would've had no viability in OU or UU without Fairy type outliving Garchomp, Tornadus-T, Greninja, and Blaziken is totally natural.