There is even a dedicated app store for it, although unfortunately it wasn’t the most well thought-out. At launch all users had to choose was “Featured” or “Manage”, meaning that users had to specifically know what app to search for if they could not find it in the Featured section. The good news is that Apple has since updated the Messages App Store and added a “Categories” section.
As you can see in the screenshot above, users will now be able to look for Messages app by category, so if you’re just after stickers you can head to the stickers section. Or if you’re looking for apps for social networking, there is a category for it as well. We can only imagine that eventually Apple will make the Messages App Store more in line with the iTunes App Store where we can see top free apps/stickers, top paid, and so on.
As an iOS user I don’t see the changes implemented yet, so we can only assume that it is being rolled out gradually so do keep an eye out for.