uBlock Origin is the must have.
Personally I also use Dark Reader, NoScript, View Page Source and User-Agent Switcher.

• ublock origin, first last and if necessary only extension you really need
• dark reader
• youtube shorts block - converts shorts links into regular video player with actual fucking seek/volume controls
• youtube sponsor block - I pay for my bandwidth, I decide what gets downloaded.
• privacy badger

uBlock Origin and nothing else. The more extensions, the more unique you're fingerprint will be and the bigger your attack surface.

Dont forget SponsorBlock if you spend any time on youtube

For keeping cookies in bento boxes:

• Firefox Multi-Account Containers
• Temporary Containers

uBlock Origin

Sponsorblock

Multi account containers

Password manager like Bitwarden

Bypass Paywalls Clean

Category "how the hell isn't this included by default" :

• Copy Plain Text: Adds an option in the right click menu to copy the selected text as plain text, without formatting
• Copy Link Text : Adds an option in the right click menu to copy the text of a link
• Markdown Reader: Show formatted markdown. I tried several extensions for this and this is the one I prefer personally. It has an index panel on the left which is sooo useful.

Category "Preserving your mental health online" :

• uBlock Origin: You really need to block those ads
• Consent-O-Matic: Never see a cookie pop-up again in your life (it auto accepts or refuse in your place).
• SponsorBlock: Skips Youtube sponsorships. You can define which ones you want to skip and which you want to watch (paid ads, self promo, etc)
• Return Youtube Dislike: Show the number of dislikes on videos. It's not a real number, it's extrapolated based on how many people with the app have clicked dislike.
• Youtube No Translate: Keeps titles, descriptions and audio tracks in their original language

Category "Usefull" :

• KeePassXC-Browser: To access your password database from your browser
• Whatever fingerprinting protection you can find (Canvas, Fonts, WebGL, etc.. half those I used have been pulled, haven't found a replacement for all of them)

Category "Would be nice if..." :

• A user agent switcher... if you want all websites to block you 😑
• NoScript: Block javascript and create custom rules to allow it only when and where you want. Or the reverse. It was great a few years ago but I've stopped using it because websites require allowing more and more otherwise nothing works and it's hell can we cancel javascript please?
• Dark Reader: Dark mode for all websites. Can make some websites unreadable, but you can turn it off for that website. Makes everything much slower though so I don't use it.

• ublock origin
• dark reader
• firenvim
• vimium
• containers

• uBlock Origin
• NoScript
• JShelter
• CSS Exfil Protection
• Libredirect
• Indie Wiki Buddy

I also sometimes use the IceCat extensions, too:

• LibreJS
• LibrifyJS
• Reveal hidden HTML
• Searxes' Third-party Request blocker
• Workarounds for nonfree JS

For android mobile I use Ironfox.

https://gitlab.com/ironfox-oss/IronFox

Its a fork of the now discontinued Mull browser.

uBlock Origin Firefox Multi-Account Contaniners (and then use them) If you use some kind of webmail like google, hotmail, yahoo, then: Webmail Ad Blocker Remove FBclid and UTM

Optional Dark Reader Enhancer for Youtube

I'm partial to this one

For vanilla FF I use multi - account containers, uBlock, and privacy badger.

For other FF forks like Librewolf, I get more blocky, like JShelter, a random agent switcher, and if that breaks a site beyond use I try Chameleon and NoScirpt.

ublock origin, nutensor(umatrix), twp, bypass paywalls clean, dark reader, vimfx

ublock origin, dark background and light text

Adnausuem, Consent-o-matic

To support independent Wikis

• Indie Wiki Buddy

For those who are multilingual that are annoyed at websites autotranslating via a shitty ai

• Reddit Untranslate
• Youtube Anti Translate

To make Youtube better

• SponsorBlock
• YouTube Row Fixer
• Hide Youtube-Shorts

For me:

• uBlock origin
• Libredirect
• Decentraleyes (Although I don't really know how much it really helps for privacy)

Depends on the user.

For me it's uBlock Origin, NoScript, Cookie AutoDelete and Binnen-I be gone

I'm not gonna lie, I'm a little bit of an extensions hoarder, which is bad for fingerprinting 😣, but I seriously do use the extra ones.

Vital:

uBlock - obviously, some people even suggest to only use this extension and nothing else to reduce fingerprinting. Make sure to enable those filters! Also check out the advanced mode, eliminates the need for NoScript.

Not Vital But Really Good To Have:

LibRedirect - Never worry again about visiting the original social media site, you can immediately be redirected to a proxy version of the site that doesn't stalk you. Great when I'm forced to click a Twitter, Reddit, Youtube, etc. link. Unfortunately, some proxy services are dead (Instagram, Tiktok, Invidious is always under threat, etc.)

Bitwarden - Password manager

Dark Reader - Nice, especially on fingerprint resisting browsers like Librewolf that don't let your browser/sites see your system settings to automatically pick the dark mode of a website. Have singed my eyes a couple times.

For Language Learners (like me):

Yomitan - The GOAT of tools, a popup dictionary that can be used to instantly look up the definition of a word in your target language, and connects with Anki, a flashcard app. I use it for making vocabulary cards from Japanese media I consume. Literally all the other resources are meant to be paired with this.

Asbplayer - Lets you add subtitles to whatever media you're streaming and makes the text selectable. Paired with Yomitan, you can easily make Anki flashcards from the TV/Movies/Videos you watch.

Lap Clipboard Inserter - By using a clipboard extension with Textractor, you can hook a game/visual novel and auto-copy all the game text to a webpage, which can be paired with Yomitan (you guessed it!) to look up words. You have to turn it on for individual pages, so don't worry about it constantly stalking you.

Neat, But Random:

Mastodon Streetpass - Helps you figure out if a person is on Mastodon by looking for a custom link on their site. Collects a list of them and tells you the date that it found the account. Basically just browse as usual and it will passively collect a list.

https://github.com/arkenfox/user.js/wiki/4.1-Extensions