Elysium RAT is a free open source RAT

Elysium RAT is a free open source Remote Administration Tool. This
project is very influenced by the legacy of DarkCoderSc and its
well-know DarkComet RAT, because of that, we thank you so much for your
inspiration.

Elysium RAT give you the ability to connect to and control your systems,
wherever you are. You can keep a close eye on your computers to
supervise the online activity of your employees or children. Furthermore
Elysium RAT can be used to monitor your system, remotely assist your
clients or family members to recover lost data or repair a computer.

The main functions of Elysium RAT are System Monitor, File manager,
Surveillance, Network functions, WIFI and so on.

Extra:
The client is programmed in VB .NET and the server in C++