GIPHY for iMessage - The easiest way to share all the GIFs in all your txts
Gifox - Delightful GIF Recording and Sharing App for macOS
Doll Up Stickers - Dress up your messages.
Giffing Tool - Giffing Tool is simply put: The fastest creator of high quality captioned GIFs available.
Bobble Stickers for iMessage - One selfie, Unlimited Stickers!
Instagiffer - Create GIFs from anything!