Adults React
2018: Try Not to Cry Challenge (YouTube)
2019: Trying Troom Troom Hacks and 5-Minute Crafts (YouTube)
2021: Guess the Christmas Movie in One Second (YouTube)
2022: Do Adults Know If These Christmas Song Lyrics Are Real?! (YouTube)
American Horror Stories
Season 1: The Naughty List (Christmas Specials Wiki; Hulu; IMDb; Wikia) This streamed in July
Ask a Ninja
2005: Ninja Santa
2009: Night Before Christmas
2010: Santa
The Awesomes
Season 2: Secret Santa (Hulu; IMDb; TV.com)
Christy's Kitchen Throwback
2019: Johnny Tsunami & Kim Possible Mele Kalikimaka Fried Rice! (IMDb; YouTube)
Dark Horse Motion Comics
Season 1: A Goon Christmas Carol (YouTube)
DC Kids Show
2017: Our DC Christmas Wish List! (IMDb; YouTube)
2017: DIY Super Hero Snow Globes and Ornaments! (YouTube)
2018: DC Kids Holiday Special with Jett and Analei (this was a live stream; video no longer available)
2019: DC Holiday Toys Preview! (YouTube)
2019: A Very DC Super Hero Girls Holiday Special! (YouTube)
2020: The Joker's Holiday Pranks! (YouTube)
2020: DC Kids Save the Holidays with Asher Angel! (YouTube)
2020: DC Kids Holiday Special! (YouTube)
DC Super Hero Girls
Season 3: It's a Superful Life (IMDb; Wikia; YouTube)
Season 5: Fortress of Solidarity (IMDb; Wikia; YouTube)
Season 5: Super Gift Swap (Wikia; YouTube)
Dollface
Season 1: History Buff (Hulu; IMDb; Wikia)
The Flog
Season 1: A Holiday Journey to Log Mountain
Season 1 also: The Flog Christmas Eve Spectacular
Futurama
Season 8 (or 11): I Know What You Did Next Xmas (Christmas Specials Wiki; Hulu; IMDb; Infosphere; TV Tropes; Wikia) This streamed in August
Grumpy Princess Show
2016: Very Grumpy Christmas (YouTube)
The Guild
2007 Extra: A Christmas Raid Carol
2008 Extra: Twas the Night Before Christmas
Hawkeye
Season 1: Actually the whole season is basically 6 Christmas episodes, especially the last one.
Into the Dark
Season 1: Pooka! (Bloody Disgusting; Christmas Specials Wiki; Hulu; IMDb; Wikipedia)
Season 2: A Nasty Piece of Work (Christmas Specials Wiki; Hulu; IMDb)
Kids Try
Season 1: Kids Try 100 Years of Christmas Desserts (Epicurious; IMDb; YouTube)
Last Week Tonight (TV series)
2019 webisode: SantaCon (YouTube)
Life Hacks for Kids
Season 1 (2014): Ho-Ho Hacks (YouTube)
Season 1 (2015): HaHa HoHo Hacks (YouTube)
Season 1 (2015): Hacky Holidays! (YouTube)
Season 1 (2016): String Light Hacks (YouTube)
Season 2 (2017): Holly Jolly Holiday Gift Hacks (YouTube)
Season 2 (2017): Gift Wrapping Hacks (YouTube)
Season 2 (2018): Shhh... Secret Santa Hacks (YouTube)
Season 2 (2018): Holi-yay! Hacks (YouTube)
Season 2 (2018): Ugly Sweater Hacks (YouTube)
Season 3 (2019): Deck Your Halls! (YouTube)
Season 3 (2019): Ha Ha Holiday Gag Gifts (YouTube)
The Marvelous Mrs. Maisel
Season 1: Thank You and Good Night (A.V. Club; IMDb; TV.com; Wikia)
Mina Murray's Journal
Season 1: Christmas Message (YouTube)
MsMojo
2023: Top 10 Greatest Santa Portrayals of All Time (YouTube)
2023: Top 20 Best Classic Christmas Songs (YouTube)
People Vs Food
2016: Weird Holiday Foods (IMDb; Wikia; YouTube)
2017: Kids Eat Foreign Christmas Food (IMDb; YouTube)
2018: Try Not to Eat Challenge - Holiday Movies (IMDb; YouTube)
2022: Try Not to Eat - Holiday Movies! (YouTube)
Princess Rap Battle
2014: Mrs Claus vs Mary Poppins (IMDb; YouTube)
React
2022: Do Teens Know Iconic Christmas Movies? (YouTube)
2023: Guess the Holiday Movie from the VHS Cover! (YouTube)
2023: Can YOU Guess the Holiday Song from the Prop?! (YouTue)
Underlined
2019: Team Underlined's 2019 Holiday Gift Guide (YouTube)
2020: Monthly Must Haves: December 2020 (YouTube)
What If...?
season 2: What If... Happy Hogan Saved Christmas? (IMDb; MCU Wiki; TV Tropes; Wikipedia)
What They Got Right
2018: Elf Without Will Ferrell?! (IMDb; YouTube)
WordPlay
2013: Krampus' First Christmas (YouTube) This isn't actually an episode of WordPlay, but an episode of it led me to watch this video.