Quoted By:
Vaporeon, Jolteon and Flareon are all pretty clever extrapolations of Eevee's design based on their theme. They're the best.
Espeon takes a folklore approach. It's good.
Umbreon and Sylveon's designs don't really have anything to do with what they do and are just generically "dark" and "fairy" but are functional and distinctive.
Leafeon is a cat with leaves taped to it. This has always been the bottom of the design barrel for Grass types. Leafeon is intensely disappointing.
Glaceon doesn't even try to have an ice theme. Leafeon at least has the leaves taped to it. Glaceon's only visual indication it might be Ice type is being pale blue- it's a cat with a princess cut, not at all visually representative of its type. With arctic foxes, snow leopards and bobcats being real animals they literally already had their work done for them and they still fucked it up somehow. Glaceon is one of the worst designs in the franchise.