[S3xySmurf]

There are tons on github.

https://github.com/AhMyth/AhMyth-Android-RAT
https://github.com/AdvancedHacker101?tab=repositories ~ Cross OS and you need to build everything yourself but worth it.
https://github.com/globalpolicy/PhoneMonitor

These are the most up to date source codes after a quick browse.

Also you can use a legitimate apk file and backdoor it for use with MSF, https://github.com/dana-at-cp/backdoor-apk

There's many reasons to stay away from Dendroid unless you plan on updating the panel itself and fixing the numerous bugs in the code, it's not the best tool for the job, it works but it's by far nowhere near updated as it should be, https://0day.today/exploits/24317#popup_welcome_div this lovely Remote Code Execution Vulnerability in the panel proves my theory.