• NewPipe has made my YouTube watching experience way better; it’s a standalone app with features like ad blocking, subscriptions, and downloading.
• F-Droid (particularly the Droid-ify client) is an open-source app store that generally provides quality apps.
• Obtanium has helped me stay up to date with some of my more obscure apps, which are released only on Github. Obtanium can auto-update apps from a GitHub link or similar, which makes the process way easier.
• Auxio is a pretty good music player, it’s quite lightweight but it also looks good.

All of these are available on F-Droid, I find that many F-Droid apps provide a better or cleaner experience than Google Play apps.