Kakao Emoticon Studio

https://emoticonstudio.kakao.com

Submission Guidelines

• 32 static
  • 360px x 360px
• 24 moving
  • 360px x 360px
• 16 moving big
  • ?px x ?px
• Takes ~4 months to get approved

Apple Stickers

https://developer.apple.com/app-store/sticker-submissions/

Submission Guidelines

• Developer Account ($99)
• Development Guide
  • https://developer.apple.com/stickers/

• Sticker packs are created using a set of image files in PNG, JPEG, or GIF format. They can also be animated images in APNG or GIF format. Learn more about creating images that work well as a sticker pack by reading the Human Interface Guidelines.

  • Human Interface Guidelines: Messaging
  • Creating Stickers with Motion
• ​Dimensions (300x300, 408x408, 618x618)

Line Creators Market

https://creator.line.me/en/

Submission Guidelines

• Creators receive 50% of sticker and theme revenue (after deduction of the 30% fee charged by Apple, Google, etc.).
• Production Guidelines: https://creator.line.me/en/guideline/sticker/
• Review Guidelines: https://creator.line.me/en/review_guideline/
• They accept APNG (Animated PNG) format.