Top 20 NuGet MEssaging Packages

Plug-in providing message-publisher allowing commands and domain-events to be published to RabbitMQ. Also provides attributes used to binds in-process message handlers to RabbitMq queues to be invoked when messages arrives on queue.
The most popular open-source service bus for .NET
NServiceBus Azure Storage Persistence
An adaptor to allow EasyNetQ to use LightInject as its internal IoC container
An adaptor to allow EasyNetQ to use SimpleInjector as its internal IoC container
Catel.Core library.
Package Description
Sql persistence for NServiceBus
High performance Redis client, incorporating both synchronous and asynchronous usage.
Library of lightweight WCF-based service bus with queue and topic support for secure event-driven messaging between disjointed systems.
Framework for enabling time-series data processing services including hosted input, action and output adapter implementations.
MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker).
NServiceBus.Newtonsoft.Json
A 100% native C# port of the lightweight high performance messaging library ZeroMQ
An adaptor to allow EasyNetQ to use Castle.Windsor as its internal IoC container
StackExchange.Redis.Extensions is a library that extends StackExchange.Redis allowing you a set of functionality needed by common applications. This implementation is based on Protobuf serializer.
Pluggable foundation blocks for building distributed apps.
A lucene style query parser that is extensible and allows additional syntax features.
Plug-in providing in-process messaging with extension points other plug-ins can extend to provided additional messaging patterns.
NServiceBus Transport for the Windows Azure Servicebus