BenchmarkDotNet.Core by: .NET Foundation and contributors

Powerful .NET library for benchmarking

BenchmarkDotNet.Toolchains.Roslyn by: .NET Foundation and contributors

Powerful .NET library for benchmarking

BlazorStrap by: Chanan Braunstein, John Bomhold

A bootstrap 5 component library for Blazor

Bogus by: Brian Chavez

A simple and sane data generator for populating objects that supports different locales. A delightful port of the famed faker.js and inspired by FluentValidation. Use Bogus to create UIs with fake data or seed databases. Get started by using Faker class or a DataSet directly.

bootstrap by: Mark Otto, Jacob Thornton

Sleek, intuitive, and powerful mobile first front-end framework for faster and easier web development.

CommandLineParser by: gsscoder, nemec, ericnewton76, moh-hassan

Terse syntax C# command line parser for .NET. For FSharp support see CommandLineParser.FSharp. The Command Line Parser Library offers to CLR applications a clean and concise API for manipulating command line arguments and related tasks.

ConsoleAppFramework by: Cysharp

Zero Dependency, Zero Overhead, Zero Reflection, Zero Allocation, AOT Safe CLI Framework powered by C# Source Generator.

CsQuery by: James Treworgy

CsQuery is a CSS selector engine and jQuery port for .NET 4 and C#. It implements all CSS2 and CSS3 selectors, all the DOM manipulation methods of jQuery, and some of the utility methods. It includes an HTML parser, a document object model that mimics the browser DOM, and uses a subselect-capable index for fast operation.

CsvHelper by: Josh Close

A library for reading and writing CSV files. Extremely fast, flexible, and easy to use. Supports reading and writing of custom class objects.

Dapper.ColumnMapper by: Dan Turkenkopf

Simple extension to [Dapper](https://code.google.com/p/dapper-dot-net/) to allow arbitrary column to property mapping

Docker.DotNet by: Docker.DotNet

Docker.DotNet is a library that allows you to interact with the Docker Remote API programmatically with fully asynchronous, non-blocking and object-oriented code in your .NET applications.

DocumentFormat.OpenXml by: Microsoft

The Open XML SDK provides tools for working with Office Word, Excel, and PowerPoint documents. It supports scenarios such as: - High-performance generation of word-processing documents, spreadsheets, and presentations. - Populating content in Word files from an XML data source. - Splitting up (shredding) a Word or PowerPoint file into multiple files, and combining multiple Word/PowerPoint files into a single file. - Extraction of data from Excel documents. - Searching and replacing content in Word/PowerPoint using regular expressions. - Updating cached data and embedded spreadsheets for charts in Word/PowerPoint. - Document modification, such as removing tracked revisions or removing unacceptable content from documents.

DotLiquid by: Tim Jones, Alessandro Petrelli

DotLiquid is a templating system ported to the .NET framework from Ruby’s Liquid Markup.

DotNetAnalyzers.PublicApiAnalyzer.Unstable by: Sam Harwell et. al.

An analyzer for packages with public APIs.

EPPlus by: EPPlus Software AB

A spreadsheet library for .NET framework and .NET core

Fable by: Alfonso García-Caro Núñez

F# to JS compiler

FastEndpoints by: FastEndpoints

A light-weight REST Api framework for ASP.Net 6 and newer that implements REPR (Request-Endpoint-Response) Pattern.

FluentAssertions by: Dennis Doomen, Jonas Nyrup

A very extensive set of extension methods that allow you to more naturally specify the expected outcome of a TDD or BDD-style unit tests. Targets .NET Framework 4.5 and 4.7, as well as .NET Core 2.0, .NET Core 3.0, .NET Core 2.1, .NET Standard 1.3, 1.6, 2.0 and 2.1. Supports the unit test frameworks MSTest, MSTest2, Gallio, NUnit, XUnit, MBUnit, MSpec, and NSpec.

FluentValidation by: Jeremy Skinner

A validation library for .NET that uses a fluent interface to construct strongly-typed validation rules.

Google.Protobuf by: Google Inc.

C# runtime library for Protocol Buffers - Google's data interchange format.