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!
"uBlock" does not need any kind of introduction. Most of the people who answered the thread use it anyway. But it is my favourite!
"Language tool" to help me spell things properly, lol
"I don't care about cookies" to get rid of annoying GDPR-compliance banners
"FoxyProxy" to easily switch between proxies
"Vimium C" to navigate the web using vi-like shortcuts
"SponsorBlock". I don't use YouTube as much nowadays but when I do, this add-on helps me skip in-video advertisements and irrelevant moments
"Search by image"
"Rikaichamp" is a great add-on for anyone who often needs to look up Japanese words
"Runet Censorship Bypass" because censorship circumvention is not a crime in my country. Yet.
Honestly, I thought it will be shorter. It makes me appreciate the authors of all these add-ons even more. If it weren't for their efforts, web browsing would be a much less enjoyable experience.
In case you didn't know, the "I don't care about cookies" extension was recently sold to Avast. I don't know if anyone has seen them make any sketchy changes yet, but personally I didn't want to trust them and uninstalled it
Oh, well, that's too bad. Thank you for pointing this out!
Apparently, there is now a debloated fork "I still don't care about cookies" but the last update was in February and the issues are all open.
Why fork?
This extension has been acquired by Avast and I simply don't trust Avast with my data. Additionally, having it on Github allows us to improve the code and add support for websites faster.
You could try Consent-O-Matic. That’s what I use. It also doesn’t simply agree to everything like the other one but chooses the most privacy-friendly option instead.