"Holiday Knights", from The New Batman Adventures (1997), is a collection of three short stories. The middle one, in which Batgirl battles Clayface, has been posted previously. In addition.......
Harley Quinn (Arleen Sorkin) and Poison Ivy abduct & hypnotize Bruce Wayne (Kevin Conroy), using Ivy's hypnotic lipstick. They use Bruce's credit cards to go on a holiday shopping spree.
In the finale, Batman & Robin battle the Joker (Mark Hamill). Not exactly the sequel to "Christmas With The Joker", but....!
Yes, believe it or else, it was the first episode aired. In September. Go figure.