Google has updated its Gboard beta which is a mobile keyboard supported for Bitmoji and stickers. Last year, it only supported Android 7.1 but quickly it came out for older android versions as well. You can now insert stickers and Bitmoji also.
There is a sticker tab that can be used from the overflow menu or top button bar. You can also switch between the emoji button and sticker tab at the bottom by pressing it eventually. Installation of Bitmoji app and download stickers pack is available for both.
By installing it, all the stickers are available to use. you can search for stickers like a search for gifs. Still, there is some twist in this update, like in its shift, backspace buttons, and theme dashboard.
If you want to try Gboard beta 6.5, you can get it from the testing program but first, you need to sign up for this and install the latest version. You can also download it from APKMirror.