I would change Umbreon's shiny to lime green with black rings, to better match its partner Espeon's shiny form!
(I know that Eevee isn't based on a cat—it's just a fantasy animal that resembles a cat and a dog (though at least one of its evolutions clearly is based on a cat))
but I'd prefer to think of it as a cat
White Garchomp with black and lime green details, its current shiny is pretty lame.