DC’s Legends of Tomorrow The CW’s four-night superhero crossover event concludes as the Legends are joined by Supergirl, the Flash and Green Arrow (Melissa Benoist, Grant Gustin, Stephen Amell) to do battle with the alien Dominators. 8 p.m. KTLA
Rosewood Dr. Daisy Wick (Carla Gallo) from “Bones” makes a crossover appearance on a new episode of the Miami-set forensics drama. 8 p.m. Fox
The First 48 This true-crime series returns with new episodes. 8 p.m. A&E
Regular Show The kooky animated comedy about a bluejay and a raccoon offers its own Christmas episode. 8 p.m....