LINE Creators Market is a service designed to let anyone create, submit, and sell their own stickers for use in LINE chats. via Link
If you are a designer, you can start selling your own stickers on LINE Creators Market. The messaging app currently has about 400M users so this can be a great potential part-time gig for designers.
The LINE Creators Market works a bit like App Store, you submit your designs and await for approval, plus Line takes a 50% cut. Currently any users around the world can register as a creator and submit stickers but the stickers are only sold in supported countries (Indonesia, Japan, Taiwan, and Thailand).