SketchKeys - Learn Sketch shortkeys easily w/ keyboard stickers
Acrylic Charms by Sticker Mule - Add some charm to your life.
Stickered for Messenger - Add stickers to a photo and send them to friends
Sticker.Place API - Get stickers for your app
Duckey - iOS keyboard for sending animated stickers
StickerPop API - Embed all the best stickers and GIFs into your apps.