Updates:
Insimenator
Sims 4
Still running its donation drive
http://www.insimenator.org/index.php/topic,115536.0.html
Around the Sims
Sims 4
Advent Calendar started
https://sims4.aroundthesims3.com/
Alixdekostube
Sims 4
Advent Calendar
https://alixdekostube.tumblr.com/tagged/advent-calendar
Simthropology
Sims 4
Birthday countdown
https://simthropology.tumblr.com/tagged/birthday-countdown-19
Dream Central
Sims 4
Advent Calendar
https://raiichuu.tumblr.com/tagged/raiichuus-advent-calendar
All4Sims
Sims 4
Advent updates
http://www.all4sims.de/index.php?page=Thread&threadID=15467
Christmas update
http://www.all4sims.de/index.php?page=Thread&threadID=15502
Sims Dreams
Sims 4
Advent Calendar
https://www.sims3dreams.at/Forum/misc.php?page=Adventkalender
Digi
Sims 4
Doing Giftmas
https://digi-cu.tumblr.com/
The Ninth Wave Sims
Sims 4
Sim
http://www.theninthwavesims.com/search/label/The%20Sims%204
Annett’s Sims 4 Welt
Clothing
http://annettssims4welt.blogspot.com/
Blacky’s
Sims 4
Wall clocks, Advent Calendar - Door 21 & 22
http://www.simszoo.de/
Mod the Sims
Sims 4
House, portrait, spells and potions mod
http://www.modthesims.info/browse.php?gs=4&f=38&showType=2