It is painful and completely unnecessary to browse the internet with advertisements. uBlock Origin provides a clean, easy, and most importantly open-source solution to declutter the web. uBlock allows for custom filter lists and on the fly element blocking to suit your needs.
I've always been a big fan of dark mode, and with Dark Reader, I can have it anywhere. It's very easy to toggle on and off when sites aren't cooperating, but otherwise this has been my go to solution.
This extension completely changed the way I interacted with the web. Hover Zoom does exactly what the name entails: hover to zoom into images/videos on any website. This is extremely helpful on Reddit, Twitter, Wikipedia, etc. Any site that hosts images benefits from this feature. The project is open-source and is frequently updated to add support to different sites.
Nicely paired with Hover Zoom, Search by Image is also as simple as it sounds. Right clicking an image lets you access several reverse image services instantly. It is also open-source!
WebP is annoying. I don't care for the efficiency, plus the lack of adoption makes it gross. Save webP as solves this annoyance for the better.
Bypass Paywalls Clean is an "install and forget" type of extension. Read the New York Times, The Atlantic, and any other site plagued by a paywall without any interruptions. You know an extension is effective when it's been removed from both Firefox and Chrome's extension stores due to DCMA takedowns.
SponsorBlock allows users to specify sponsored segments in videos so others can skip over them easily. Even though I pay for YouTube Premium, I still get plenty of use out of this extension.
The successor to Enhanced Steam, Augmented Steam is essential for browsing around the Steam store and community. Price charts and history added to games, community market quality of life features, and more.
Checks bans of people you recently played with or in friends lists. Can also scan entire Counter-Strike match history.
I used to use CSGO Trader Extension as it displayed very detailed information on skins, trades, and more. However, I've never really been much of a trader, and the market revolves around CSFloat now anyways. Plus, that particular extension abuses your API key to the point where Steam's rate limiter kicks in, which makes browsing the site a pain in the ass. CSFloat's own extension doesn't do this, and displays only the essentials. I have no urge to switch back.
Twitch might have the most intrusive methods of advertising on any website. It is pretty much impossible to enjoy even a smidgen of content on this site without being bombarded by something. Here's a quick guide to eradicate these ads. This method swaps the stream with lower-resolution video during ads.
I basically only use BetterTTV for emotes (BTTV + 7TV). The other features are just a nice bonus.