Fill your 5e game with holiday cheer!

Double0Games' Holiday Monsters book contains 7 monsters to make your PCs hate the holidays. 

The Krampus (CR 15) 
A child-snatching devil who abducts the naughty.

Santa Claus (CR 16)
A celestial gift-giver that brings good cheer, and occasionally beats people to death with a frost glaive.

March of Broken Toys (CR 8)
A motley collection of toys that drag creatures to the ground and tear them apart. 

Fey Treant (CR 11)
It's a magic Christmas Tree.

Yule Cat (CR 12) 
A gigantic cat that enforces holiday traditions, by eating those that don't conform. 

Jack Frost (CR 20)
An immortal creature of immense elemental power, that sometimes does unspeakably cruel things for diversion.

Snow Golem (CR 10)
Man-eating snowman. Yeah, I know.

Give the gift of grisly death to your PCs. Or you know, maybe have them fight alongside Santa, whatever. As long as you buy the book, we don’t care.