APK Editor Studio - APK Editor Studio is an open-source Android application editor that allows you to edit APKs with the help of reverse engineering.
APK Studio - APK Studio is an open-source Integrated Development Environment that allows you to recompile and decompile Android applications with its unified interface.
JADX - JADX is a decompilation tool that can produce Java Source code from Dex and Apk files, being capable of providing human-readable java classes, it reverses AndroidManifest.
Apktool - Apktool is an all-in-one tool that can extract all the resources inside an APK.
Xposed Framework - Xposed Framework is an application that allows you to tweak and modify the Android system behavior without making changes to system apps.
APKInspector - APKInspector is an open-source application that you can use to lookup the Android APK information and get the app insights.