Basic JSON Formatter
Adds a page action to pretty-print JSON. Unlike similar extensions, this simply pretty-prints it. It doesn't add any kind of viewer, colors, or collapsing. If you want this to work as expected, disable devtools.jsonview.enabled in about:config.
2,590 users
Merge Windows
Merges the tabs from multiple windows together into one window. Extension won't show context menu item when there aren't more than one window of the same type to merge together. Private windows will only merge with private windows not normal.
2,570 users
Old Twitter Layout (2025)
An extension that returns old Twitter's look from 2015 or 2018. WORKS IN 2025!
2,525 users
YouTube™ dual subtitles
Automatically switch to local language, bilingual subtitles, subtitle download, subtitle dubbing, custom subtitle style. Default subtitles: Set the translation language.
2,516 users
BetterBLOX - Better Roblox Extension
BetterBLOX is a Better Roblox Extension that shows when users were last online. Plus free server region selector and player notifications.
2,499 users
Vertical Tabs Reloaded
This Firefox add-on arranges tabs in a vertical rather than horizontal fashion. Hide and display manually the tab sidebar with a hotkey (Ctrl+Shift+V) or by clicking on the VTR icon.
2,444 users
Open Subtitles
Add subtitles to any HTML5 video sites such as Youtube, Netflix, Amazon Prime Video, Disney+, HBO Max and other stream sites.
2,426 users
Highlight This: finds and marks words
Automatically finds and highlights words and phrases on the web page according to your list
2,391 users
Popupblocker
Popupblocker can block every popup. Many websites open new windows with ads, when you try to mark text or click something. This add-on will block these and show a really small notification.
2,388 users
Music Mode for YouTube™
Hides the video and thumbnails on YouTube. Blocks the video keeping only the audio on YouTube Music. Additionally, it removes the ads from YouTube and allows YouTube to play in the background on mobile. Easy to use with many options.
2,345 users
Pesticide
This extension inserts the Pesticide CSS into the current page, outlining each element to better see placement on the page.
2,333 users
Copy All Tabs
Copy All Tabs takes the address and title for each tab and creates a text list of links. The list is copied to your clipboard so you can paste it to your notes. You can also open tabs from a previously saved list of links. Similar to CopyAllUrls.
2,285 users
Reddit Enhancer
Various tweaks to customise your Reddit experience. Supports all versions of Reddit.
2,269 users
Reader View
Strips away clutter like buttons, background images, and changes the page's text size, contrast and layout for better readability
2,263 users
