LibRedirect. Excellent one, that.

Sidebery on Firefox. Life changer for organising tabs.

Imagus feels like in an alternate universe it could be default browser behavior. When you hover over an image it will expand to full resolution and then you can press buttons to open in new tab, download, zoom in, etc.
Works on pretty much any website and is nice if the website has sized the images too small or if your eyesight is less than great.

I really only run 3 addons in Firefox currently. Chrome is the same but without UBlock.

• UBlock Origin
• BitWarden
• Streetpass for Mastodon

I try to use a minimum for performance reasons. My big three are uBlock Origin, Dark Reader and a password manager.

Kill Sticky is a really good one, makes even the most bloated websites readable.

These are a bit unique from the lists everyone else has, I think:

• Lemmy Keyboard Navigation (like the kbd shortcuts from RES)
• Google Popup Blocker (stop the annoying log in with Google popups everywhere on the web)
• OneTab (this one lets you collapse a whole window of tabs down into a list in the OneTab tab that you can later reexpand into a window again when you re-attack whatever subject all the tabs were about)

These are the more standard ones that everyone seems to run:

• UBlock Origin
• Reddit Enhancement Suite
• 2FAS Extension
• BitWarden

Vimium C

uBO, Facebook container, Bitwarden, Privacy Badger. People say uBO already covers Privacy Badger but I like keeping it there because of the replace widget feature.

Ublock Origin, dark reader, bitwarden and user agent switcher if websites are throwing a fit about firefox.

I want my RSS

Detrumpify

Outside of what has already been mentioned, I still don't care about cookies and cookie autodelete in tandem. The first accepts cookies. The second deletes them when you are done.

I haven't seen these mentioned but they are kinda niche though. I use them for work more than personal usecase but maybe someone else finds them useful.

Copy on select - highlighted text is automatically copied

Snap links - open multiple links or check several boxes using a click-drag interface