1. Androguard - Reverse engineering, malware and goodware analysis of android applications.
https://github.com/androguard
2. Android platform APIs.
https://developer.android.com/reference/packages
3. Androwarn - Yet another static code analyzer for malicious android applications.
https://github.com/maaaaz/androwarn
4. Apktool.
https://ibotpeaches.github.io/Apktool/
5. Common vulnerabilities and exposures (CVEs).
https://cve.mitre.org