Best native apps? It depends on what you need... Muuzik! (folder based music player), OSM Scout (openstreetmap offline), Piepmatz (for Twitter), Quickddit (for Reddit), LLs vPlayer (videos player), TwitchTube and so many more apps

Best store for Android apps is probably Yalp Store (which downloads apps from Google Play store) and F-Droid (only opensource apps, and you can download there the Yalp Store)