Here are the places you need to know about:
Dollhouse Mafia: (Telegram)
https://t.me/d0llh0usemafia {Patreon exclusives only. Make sure you read their rules.}
Dollhouse Mafia Booty Channel: (Telegram)
https://t.me/joinchat/RmpTnSVgxVqg7kTJ {Just the booty. No chatting.}
Dollhouse Mafia TSR Booty Channel/Requests: https://t.me/joinchat/jv00db0sv-o2MjEx (Telegram) -- A place to request content that is behind TSR/Simsdom's ad-walls.
Purr_Sabbath (Telegram)
https://t.me/joinchat/Tul0iGf1HYUSITue {Mainly patreon exclusives. Sometimes early access stuff slips in}
TS4 Rebels: https://www.reddit.com/r/TS4_Rebels/ {Early access + exclusive content. Make sure you read their rules on requesting.}
Sims Galaxy (VK):
https://m.vk.com/club164515951?q=%23freepatreonKemono Party: https://kemono.party (Basically it's the new yiff.party, so be prepared to have to search through some furry porn to find sims stuff)
Sims 4 Planet: http://sims4planet.net/ (If you can handle translating the russian, I've been told there are some gems to be found here)
Yet another russian sims site: https://href.li/?http://sims-new.my1.ru/publ/ Same as above ^
Sims 4 Direct Download Links: (telegram)
https://t.me/joinchat/vKLMamg3KW5iMDkx -- Primarily direct downloads to get around ad.f*y and other shorteners.
WCIF The Sims 4: (Telegram)
https://href.li/?https://t.me/joinchat/UvzduvlA0dk3OWNk - A WCIF channel
If anyone else knows of other places, feel free to share. But these are the main places people have been flocking with the booty gone.