As long as Apple will block third party browser engines via Rule 2.5.6 I will use Android. See open-web-advocacy.org and appfairness.org
Here my list of Android Apps I like.
OpenScan create PDFs with the camera.
Open-Source
Anki is a flashcard App for learning.
Open-Source
Osmand Open Street Map for Android.
Open-Source
Zxing Barcode-Scanner
Open-Source
GBoard Alternative (on-screen) keyboard.
Broadband measurement by the Federal Network Agency Germany