Obtainium is one that I have been using for over a week now. It keeps all my FOSS apps up to date. I have 30 apps added now, and 80% of them are now updated directly from their github page!
K-9 Mail, soon to be Thunderbird (Play Store / F-Droid / GitHub) - No-nonsense e-mail client
NewPipe (F-Droid / GitHub) - YouTube client for privacy, has no ads, supports background playing, local subscription lists, and ability to download videos
Techmino (GitHub) - FOSS Tetris clone with no ads and multiple modes, definitely my favourite
Waistline (F-Droid / GitHub) - Calorie counter app that stores all data locally. Need to add products yourself but have full control.
Antennapod is a Free Open Source Software (FOSS) podcast app. The app is well designed with great features. You can also use it for playing audio books locally as well.
With all the social media corps going full ham on advertising, I'm going to make the switch from Chrome to Firefox with ad-blocking add-ons. However, I'm at a crossroads since there are many variations ranging from the official Firefox app to Firefox Nightly and even Fennec or Fenix.
For self hosted music lovers, I would like to introduce you to Tempo, an open source and lightweight music client for Subsonic, designed and built natively for Android.
Musicolet is my favorite local music player because of the ability to switch between queues without losing the position of the last played track. I don't understand how not all music player have the same feature
Fdroid -> StreetComplete very easy contributing to osmMaps. You know your neighbourhood? Answer questions if that trafic lights have sound indication for blind people or about the type of surface that bike line has.
Moshidon is a fantastic Mastodon Client.
Kotatsu is my personal favorite Manga reader on Android.
Image Toolbox is a great choice for an open source mobile image editor with a good amount of features.
I'm looking for a Mastodon app. The official app and website really sucks for viewing threads. I prefer the comments to be nested like on Lemmy, but the official one stacks them all. Are there any recommendations?