Good targets for this include Tindangle Dholes, Archfiend Heiress, and certain Burning Abyss monsters
Its particularly good in a +1/+1 counters deck because of this: not only can you grow it to reanimate more, but creatures are usually smaller in these archetypes, so you can bring back more creatures with them
This is where all of the vanilla commanders from Legends go
In short, Umbreons value in the Pokemon TCG is a combination of nostalgic love, modern card-pull hype, and shortage difficulties
If you do, choose an opponent to also copy it
Looking at a picture of a Shadowless version and a regular version can help you to see the difference