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.

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).

FastEndpoints by: FastEndpoints

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

FastEndpoints.Swagger by: FastEndpoints

Swagger support for FastEndpoints.

FastExpressionCompiler by: Maksim Volkau

FastExpressionCompiler is 10-40x times faster than Expression.Compile()

FluentValidation by: Jeremy Skinner

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

Fluid.Core by: Sebastien Ros

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

Fody by: Fody

Extensible tool for weaving .net assemblies.

Fortress.Facilities.Logging by: @fir3pho3nixx @hikalkan

Unofficial Castle Windsor on dotnet core

Fortress.Windsor by: @fir3pho3nixx @hikalkan

Unofficial Castle Windsor on dotnet core

Fractions by: Daniel Mueller

The fraction data type consists of two BigInteger values for numerator and denominator. It implements various operations (addition, subtraction, multiplication, division and remainder) with operator overloads.

Google.Protobuf by: Google Inc.

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

HangFire by: Sergey Odinokov

Incredibly easy and reliable way to perform fire-and-forget, delayed and recurring long-running, short-running, CPU or I/O intensive tasks inside ASP.NET application. No Windows Service / Task Scheduler required. Even ASP.NET is not required. Backed by Redis, SQL Server, SQL Azure or MSMQ. http://hangfire.io/

Hangfire by: Sergey Odinokov

An easy and reliable way to perform fire-and-forget, delayed and recurring, long-running, short-running, CPU or I/O intensive tasks inside ASP.NET applications. No Windows Service / Task Scheduler required. Even ASP.NET is not required. Backed by Redis, SQL Server, SQL Azure or MSMQ. This is a .NET alternative to Sidekiq, Resque and Celery. https://www.hangfire.io/

Hangfire.AspNetCore by: Sergey Odinokov

ASP.NET Core support for Hangfire, a background job framework for .NET applications.

Hangfire.Console by: Alexey Skalozub

Job console for Hangfire

Hangfire.Core by: Sergey Odinokov

An easy and reliable way to perform fire-and-forget, delayed and recurring, long-running, short-running, CPU or I/O intensive tasks in .NET applications. No Windows Service / Task Scheduler required. Backed by Redis, SQL Server, SQL Azure or MSMQ. This is a .NET alternative to Sidekiq, Resque and Celery. https://www.hangfire.io/

Hangfire.MySqlStorage by: Arnoldas Gudas

Hangfire MySql Storage