InvidioMe - Convert any YouTube Links and Videos to Invidio Links
PeerTubeify - On YouTube, displays a link to the same video on PeerTube, if it exists.
Untrack Me - Surf the web, free from tracking
FreeTube Redirect - Redirects YouTube links to FreeTube.
Nitterify - Redirect Twitter to Nitter, an alternative, privacy-friendly, interface.
Invidition - A WebExtension to redirect ALL YouTube and Twitter requests to their alternative interfaces.