You can also try these related scripts:

• GFYCAT | Show all Download Links (GIF, MP4, WEBP, WEBM) - Adds direct links to all image (.gif, .webp) and video (.mp4, .webm) formats and sizes on Gfycat.
• YouTube Me Again! - ytma! automatically converts YouTube(TM), Vimeo, Vine, Soundcloud, WebM, and MP4 links into real embedded videos.
• Gfycat-Redirect gif to HTML5 - Redirects giant or fat.gfycat.com hyperlinks to their HTML 5 video counterpart
• ShadeRoot GFYCat - Eye-friendly magic in your browser for GFYCat
• video-element-rate-controller - add keyboard shortcuts that will increase/decrease the playback rate for video elements.