Black Mamba is a Command and Control (C2) that works with multiple connections at same time. It was developed with Python and with QtFramework and have multiple features for a post-exploitation step.
Full-featured C2 framework which silently persists on webserver
...Multi-request support for large payloads (such as uploads) Provides a powerful, highly configurable settings engine. Each setting, such as user-agent has a polymorphic mode. Customizable environment variables for plugin interaction. Provides a complete plugin development API.