Here's a collection of Android apps I love. Most of them will have a specific usecase. If it's a general app, I'll explain why it's better than the alternatives.
Niagara Launcher is a home screen with a twist. Usually you have icons in a grid on a home screen. Niagara has a long list. Your home screen is a smaller list with your favorite apps, clock and maybe a widget. Notifications show up in the app list. It's very easy to handle with one hand. Scroll with the alphabet scrollbar, tap your app.
Beeper is a chat aggregator. It shows your conversations from a lot of apps in one. SMS, RCS, WhatsApp, Twitter, Discord, LinkedIn and a few more. It's nice to only have to check one app.
Wavelet is an audio equaliser (EQ). It adjusts your headphones' sound to make it more balanced. Are your Sony earbuds too bass-heavy? Wavelet has a profile for your earbuds, so they sound more neutral.
KDE Connect is the best way to connect your phone to your PC. I am using it with Windows and Linux (Gnome). It can sync notifications, clipboard music and more. I find it works better than Link to PC on Windows. You have to install the KDE Connect program on your PC too.
Tasker is a paid tool for automation. I vaguely know it's similar to Apple Shortcuts. I am using it to turn on Do Not Disturb while at work and turn it off when I leave. Before I automated this, my phone would often stay silent. Tasker can be a lot more powerful than my use case.
OsmAnd is a navigation app. It's similar to Google Maps. OsmAnd the app for Open Street Maps. Open Street Maps has a lot more data, especially for footpaths and small bike routes. It has information on traffic lights, benches and speedbumps. It also has a great offline mode. When I started using OsmAnd, Google Maps didn't have any offline directions.