They are all known as the "Angel Pokemon"

Oculim "It is a being made of pure light. There is a legend that states you'll see a vision of your future if you look directly in it's eye."

Cherion "This adorable Pokemon has inspired many artists to create decorations to be used around the holidays. It wouldn't be wise to use an actual Cherion as a tree topper however."

Archangelos "These powerful creatures strike fear into the humans who hold a strong faith. Some speculate that these beings are messangers from Arceus."

Shiny version