Something I call Event Stream Assistant. I found myself commonly having to code small utilities for message brokering management/assistance (over and over again)- for the simple things like:
Flat File Processing,
Flat n' Sort,
Single State,
Single State Merge,
CnC (CLI for managing (SAS) ESP projects).
Logic Engine (basic logical engine / schema interpreter)
Pika (AMQP), MQTT wrappers, and Websocket Async services...
Some of these items are in production environments. I plan on releasing it open source (fully) once I get around to it. It's really useful.