>>24957247Porygon2 with eviolite is insane. It's the one thing I can consistently wall any of my friends with because it has access to recover, STAB Tri-Attack and a plethora of other useful and powerful moves. You can literally just sit there and shit all over people with it. Never tried with a Chansey, but I'm sure that it becomes just as useful.
Those are rare cases though, considering both Porygon2 and Chansey were already huge tanks when their evos were introduced. It's also offset by the fact that they aren't necessarily *powerful*, just bulky.
I'd love to see some more new evolutions for things that deserve them, like perhaps a Ledian evolution that makes it an actually viable mon with a big stat boost. I don't see anything that could reasonably be given an evolution that would absolutely break the game due to Eviolite. As far as I can recall there aren't any gigantically bulky pokemon that have a third spot open to evolve, other than Avalugg, and due to Ice typing, well... we'd probably be better off using an actual evolution of it if they get smart and give it something to offset the terrible ice typing.