EntityFramework by: Microsoft

Entity Framework 6 (EF6) is a tried and tested object-relational mapper for .NET with many years of feature development and stabilization.

Enums.NET by: Tyler Brinkley

Enums.NET is a high-performance type-safe .NET enum utility library

EPPlus by: Jan Källman

A library to manage Excel spreadsheets, using OOXML.

EPPlus.Core by: Vahid Nasiri

EPPlus.Core is an unofficial port of the EPPlus library to .NET Core.

Esprima by: Sebastien Ros

Standard-compliant ECMAScript 2016 parser (also popularly known as JavaScript or ES6).

ExcelDataReader by: ExcelDataReader developers

Lightweight and fast library written in C# for reading Microsoft Excel files (XLS, XLSX).

ExCSS by: Tyler Brinks

ExCSS is a CSS 3 parser for .NET. ExCSS makes it easy to read and parse stylesheets into a friendly object model with full LINQ support.

ExtendedNumerics.BigDecimal by: https://github.com/AdamWhiteHat

Arbitrary precision decimal class

Fare by: Nikos Baxevanis

.NET port of dk.brics.automaton - Project Fare is an effort to bring a DFA/NFA (finite-state automata) implementation from Java to .NET. There are quite a few implementations available in other languages today. This project aims to fill the gap in .NET.

FirebirdSql.Data.FirebirdClient by: FirebirdSQL

Firebird ADO.NET data provider

Fizzler by: Atif Aziz Colin Ramsay

Fizzler is a W3C Selectors parser and generic selector framework for document hierarchies.

FluentFTP by: Robin Rodricks FluentFTP Contributors

An FTP and FTPS client for .NET & .NET Standard, optimized for speed. Provides extensive FTP commands, File uploads/downloads, SSL/TLS connections, Directory listing parsing, File hashing/checksums, File permissions/CHMOD, FTP proxies, FXP transfers, UTF-8 support, Async/await support, Powershell support and more. Written entirely in C#, with no external dependencies.

FluentMigrator by: Josh Coffman Tom Marien

FluentMigrator is a database migration framework for .NET written in C#. The basic idea is that you can create migrations which are simply classes that derive from the Migration base class and have a Migration attribute with a unique version number attached to them. Upon executing FluentMigrator, you tell it which version to migrate to and it will run all necessary migrations in order to bring your database up to that version. In addition to forward migration support, FluentMigrator also supports different ways to execute the migrations along with selective migrations called profiles and executing arbitrary SQL.

FluentValidation by: Jeremy Skinner

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

FluentValidation.AspNetCore by: Jeremy Skinner

AspNetCore integration for FluentValidation

Fluid.Core by: Sebastien Ros

Fluid is a template engine based on the Liquid markup, with focus on performance and .NET programming patterns.

Flurl by: Todd Menier

A fluent, portable URL builder. To make HTTP calls off the fluent chain, check out Flurl.Http.

Flurl.Http by: Todd Menier

A fluent, portable, testable HTTP client library.

Fody by: The Fody Team

Extensible tool for weaving .net assemblies.

FodyHelpers by: The Fody Team

Helpers for Fody.