MassTransit by: Chris Patterson Dru Sellers Travis Smith

MassTransit is a distributed application framework for .NET, including support for MSMQ and RabbitMQ.

MaterialDesignThemes by: James Willock

ResourceDictionary instances containing Material Design templates and styles for WPF controls in .NET.

lz4net by: Milosz Krajewski

LZ4 is lossless compression algorithm, sacrificing compression ratio for compression/decompression speed. Its compression speed is ~400 MB/s per core while decompression speed reaches ~2 GB/s, not far from RAM speed limits. LZ4net brings LZ4 to all (most?) .NET platforms: .NET 2.0+, .NET Core, Mono, Windows Phone, Xamarin.iOS, Xamarin.Android and Silverlight

log4net by: The Apache Software Foundation

log4net is a tool to help the programmer output log statements to a variety of output targets. In case of problems with an application, it is helpful to enable logging so that the problem can be located. With log4net it is possible to enable logging at runtime without modifying the application binary. The log4net package is designed so that log statements can remain in shipped code without incurring a high performance cost. It follows that the speed of logging (or rather not logging) is crucial. At the same time, log output can be so voluminous that it quickly becomes overwhelming. One of the distinctive features of log4net is the notion of hierarchical loggers. Using these loggers it is possible to selectively control which log statements are output at arbitrary granularity. log4net is designed with two distinct goals in mind: speed and flexibility

MathNet.Numerics.Signed by: Marcus Cuda Christoph Ruegg Jurgen Van Gael

Math.NET Numerics, signed and thus with a strong name. We strongly discourage using this package and recommend using MathNet.Numerics instead, which is unsigned and weakly named.

LiteDB by: Maurício David

LiteDB - A lightweight embedded .NET NoSQL document store in a single datafile

Magicodes.EPPlus by: Magicodes

Create advanced Excel spreadsheets using .NET

LinqBridge by: Atif Aziz

With Visual Studio's multi-targeting and LINQBridge, you can write LINQ to Objects (local) queries using the full power of the C# 3.0 compiler and yet create programs that require only Microsoft .NET Framework 2.0. LINQBridge is a re-implementation of all the standard query operators introduced with Microsoft .NET Framework 3.5's System.Linq.Enumerable class.

LightInject.Source by: Bernhard Richter

An ultra lightweight Inversion of Control container for the .Net framework. See LightInject.Source for the source distribution.

LiveCharts.Wpf by: Beto Rodriguez

Simple, flexible, interactive and powerful data visualization for Wpf

Lucene.Net by: The Apache Software Foundation

Lucene.Net is a full-text search engine library capable of advanced text analysis, indexing, and searching. It can be used to easily add search capabilities to applications. Lucene.Net is a C# port of the popular Java Lucene search engine framework from The Apache Software Foundation, targeted at .NET Framework and .NET Core users.

Libuv by: Libuv

Multi-platform support library with a focus on asynchronous I/O.

ManagedEsent by: martinc

ManagedEsent provides managed access to ESENT, the embeddable database engine native to Windows. ManagedEsent uses the esent.dll that is part of Microsoft Windows so there are no extra unmanaged binaries to download and install.

log4stash by: urielha

log4stash is a log4net appender for easy logging of exceptions and messages to Elasticsearch indices. You can configure few filters to analyze log events before they got sended to Elasticsearch similar to the filters on logstash.

LightInject by: Bernhard Richter

An ultra lightweight single file Inversion of Control container for the .Net framework.

librdkafka.redist by: Magnus Edenhill edenhill

The Apache Kafka C/C++ client library - redistributable

Magnum by: Chris Patterson Dru Sellers

Magnum is a library for the larger than average developer

LinqKit.Core by: Joseph Albahari Tomas Petricek Scott Smith Tuomas Hietanen Stef Heyenrath

LinqKit.Core contains extensions for LINQ to SQL and Entity Framework. Note that Include(...), IAsync and IDbAsync are not supported.

MahApps.Metro by: Jan Karger Bastian Schmidt Dennis Daume Brendan Forster Alex Mitchell Paul Jenkins Jake Ginnivan

The goal of MahApps.Metro is to allow devs to quickly and easily cobble together a 'Modern' UI for their WPF apps (.Net 4.6.2 and later), with minimal effort.

log4net.Ext.Json by: Robert Cutajar Grzegorz Dziadkiewicz

Enable JSON logging in log4net.