In this generation there are 3 trios. The typical four-legged beasts that are inspired by the three musketeers.
Steel/Fighting equivalent to Athos, courage pokemon, is blue with yellow horns
Rock/Fighting equivalent to Porthos, corpulence pokemon, is gray and very sturdy, like a bull.
Grass/Fighting equivalent to Aramis, elegance pokemon, is green and stylized. His shiny version is completely pink.
This trio complements with the Water/Fighting pokemon, is a pony with an orange mane, like the feather of the hat of D’Artagnan. This is an event pokemon.