FilmHope - A/B test YouTube titles & thumbnails
ezgif.com - Ezgif.com is simple online gif maker and toolset for basic animated gif editing.
Vibby - Create + share highlights from any video in seconds
Instagiffer - Create GIFs from anything!
The YouTube Thumbnail Game - Guess which YouTube video thumbnail has more views
Gifsicle - Gifsicle is a powerful, simple command line tool for creating, editing, and optimizing animated GIFs.