Generally you can google the site name and then “removal request” and their portal will be visible.

Some more useful info: California maintains a list of data brokers, available Here

Also, paid services will scan these lists and initiate takedown requests on your behalf automatically. I’ve found optery to be good but there are other services as well

My answer recently with the announcements regarding penalizing users who upvote controversial posts has just been to save interesting stuff, comment rarely and post never. Hopefully lemmy can be a new home