The most popular Paleontological application in the world is already Open Source.

https://play.google.com/store/apps/details?id=com.zigis.paleontologas

• Room for data storage
• Koin for dependency injection
• Kotlin Coroutines for asynchronous tasks
• Firebase Crashlytics for health monitoring
• Jetpack Lifecycle Components for lifecycle stuff
• Single Activity + Fragments + MVVM + Use Cases for generic architecture
• AndroidX, because it's 2020
• Lottie, Picasso, Boom Menu for some UI

I guess that every developer has some kind of a sandbox to try new things. 
My sandbox are my personal apps, where I try to use things which I don't 
otherwise use at work. Paleontologas is one of such apps where I tried 
(and was disappointed yet again) new fragments, tried to use Koin instead 
of the Dagger and Room instead of Realm. Base classes were designed 
specifically for this app, so consider some things as improvisations 
and do not necessarily use them in your projects. 

Anyway, content is what makes apps special, not the code. So have some fun exploring and I am happy to hear comments on how you would have done it :)