Games & Entertainment
A very lightweight add-on that allows you to watch YouTube™ videos using Flash® Player instead of the default HTML5 player. The Flash® Player will consume less material resources (CPU, RAM) if your PC doesn't easily support HTML5 videos. Try it!
YouTube High Definition Featured
YouTube High Definition is a powerful tool that will let you automatically play all YouTube videos in HD (High Definition), turn off annotations, change video player size, auto stop videos, auto mute videos, control embedded videos and much more.
Turbo Download Manager Featured
a download manager with multi-threading support
Play YouTube™ Videos in Flash or HTML5 Player
One of the best extensions for YouTube™. All the features you need to make YouTube™ more awesome!
Fasterfox Requires Restart
STILL WORKS FLAWLESSLY AS OF 12-5-2016
The One; The Original Fasterfox Gives performance & network tweaks for Firefox. Fasterfox makes your browsing so much faster!
Make your Sites Faster than a Fox with Fasterfox for FireFox!
Google™ Translator Featured
Google™ Translator is a handy multi-language translator built on top of Google Translate. It gives you Google Translate UI feel right on your Firefox toolbar.
Right click YouTube video links on any websites, download it from context menu. Multi formats(mp4 flv 3gp), easy to use and fast to response.
YouTube Enhancer Plus Requires Restart Featured
Improve your watching experience! Ad Blocker, Autoplay Manager, Auto HD, Auto Replay, Cinema Mode, and more.
Best Unity3D, Flash and html5 games. This add-on opens game panel with a single click. New games every day! Very easy to use!
Web Messenger for WhatsApp™ brings web messenger right into your browser to chat with your friends.
YouTube to MP3 Converter and also YouTube to MP4, M4A and WEBM Downloader.
YouTube MP3 provides Audio MP3 up to 320 kbps, M4A up to 128kbps, Video MP4 and WEBM up to Maximum Available. Highest Download Quality Available. No Limits. Fast Download.
With Google™ Hangouts you can connect with friends and family while you browse internet. It brings conversations to life with photos, emoji, and even group video calls for free!
Automatically play YouTube™ videos in HD or any other preferred format, and disable autoplay for videos loaded in background tabs.
Tilt 3D Requires Restart
A WebGL-based 3D visualization of a webpage.
Youtube Unblock VPN is number one tool for unblocking youtube and any other web site!
YouTube No Buffer (Stop Autoplaying) Featured
A bulletproof approach to prevent YouTube from buffering videos
Helps users access their web services while travelling outside mainland China.
1. Install Extension
2. Play youtube video in your browser
3. Click the KV icon then click respective links to download
The most popular Keepvid.site website's Youtube Video Download Extension