Bevywise MQTTRoute - Highly scalable MQTT Broker with powerful extensions for all your IoT implementations from small to large enterprise.
mosquitto - Eclipse Mosquitto is an open source (EPL/EDL licensed) message broker that implements the MQTT protocol versions 5.0, 3.1.1 and 3.1. Mosquitto is lightweight and is suitable for use on all devices
MqttDesk by ioCtrl - MqttDesk is Cross-Platform MQTT Client developed by ioCtrl Technologies LLP.
MQTT.fx - MQTT.fx is a MQTT Client written in Java based on Eclipse Paho.
HiveMQ - HiveMQ is the MQTT based messaging platform for fast, efficient and reliable data movement to and from connected IoT devices and enterprise systems
MQTT Explorer - An all-round MQTT client that provides a structured topic overview