Mr. Hankey The Christmas Poo (S1E9)
Merry Christmas, Charlie Manson! (S2E16)
Mr. Hankey’s Christmas Classics (S3E15)
A Very Crappy Christmas (S4E17)
Red Sleigh Down (S6E17)
It’s Christmas In Canada (S7E15)
Woodland Critter Christmas (S8E14)
Black Friday Trilogy (S17E7-9)
HappyHolograms (S18E10)
Bike Parade (S22E10)
Christmas Snow (S23E10)
South Park: Post COVID (S24E3-4)
As far as Christmas episodes go, I have to go “Woodland Critter Christmas”. I can see why they went a long time afterwards without doing another one, because it just couldn’t be topped. That said, I also really love the Charlie Manson one.
TBH, I don’t really count the Black Friday trilogy as a Christmas special and certainly not Post COVID.