Apktool: Used for decompile and recompile an apk in order to modify it.
Dex2jar: Transform .dex file into a readable .jar file.
JADX: Read transformed .jar file.
Frida: Dynamic instrumentation toolkit (mostly use to inject javascritp code in the targeted app.This tool can be used not only on Android but also on on Mac, iOS, linux and Windows.
MobSF: Pentesting, malware and code analysis framework.