Firefox

• uBlock origin of course
• Dark Reader
• Open in Reader View, which allows me to open a link directly in reader view. This can actually bypass some login walls surprisingly enough.
• Activate Reader View, which allows me to force a website to render in reader view even if the browser decides not to show the icon in the address bar.
• LocalCDN which hosts some CDN resources locally (it's a more frequently updated fork of Decentraleyes)
• Open With, which allows me to open a url in another browser or another command. I mainly use it for feeding urls to yt-dlp.
• Web Archives, which allows me to open a link in Archive.org among other archive services.
• LibRedirect, which allows me to open links in privacy frontends (up-to-date fork of Privacy Redirect)

For mobile only,

• OldLander, which makes old.reddit.com more usable in mobile. I started having issues with almost every teddit instance once the API changes came in, so I decided to bypass the frontends and use reddit directly.