Similar to what ThemeForest has for themes, snippets can be sold for common elements test developers build (e.g. overlay, drop down tray, menu, ad, etc.). These snippets can be easily customizable and injectable.
I like the idea and I know that over tools have something like that.
Thanks for this article. Terrarium TV Android is possible on Oreo 8.0 but I recommend you to download from vShare Market or AC Market App Store.