GIFGIF.io is a handy online GIF editor with multitrack editing support. What you can do with GIFGIF.io Editor: import videos from YouTube, Vine and Coub; cut, crop, add subtitles; combine videos, images and GIFs; change speed (slower/faster) and direction (normal/reverse); rearrange imported clips (move them up and down as you move tracks in video editor); and copy tracks. Full features list:

• Import videos from YouTube, Vine or Coub (more supported video sites are coming)
• Cut and crop
• Add timed captions
• Import JPG/PNG images or animated GIFs
• Change speed
• Change direction (normal, reverse, ping pong)
• Combine videos, images and GIFs
• Multitrack editing
• Rearrange and copy imported clips
• No watermarks on your GIFs