Ublock Origin is an obvious one, but I also can’t stand not having Foxy Gestures anymore. It adds customizable mouse gestures, so you can set it up to have easy swipes to go back a page, reload a page, close a tab, etc, and it feels wonderful and smooth to use compared to just using the traditional buttons to do everything. Honestly it’s kinda wild to me that this isn’t more popular now that people are so used to phone gestures. It’s good for the same reasons!
I recently got into preventing browser fingerprinting and apparently extensions can make you more identifiable, so I cut down on the extensions I used and I would be on just uBlock Origin if I didn’t love Return Youtube Dislike and Sponsorblock so much