1.QuantConnect / Lean
Lean Algorithmic Trading Engine by QuantConnect (Python, C#)
Ranked by Attention Score: stars gained over the last 90 complete days
1–100 of 156 by Attention Score · Aug 5, 2026 – Nov 2, 2026 (UTC)
Lean Algorithmic Trading Engine by QuantConnect (Python, C#)
.NET Decompiler with support for PDB generation, ReadyToRun, Metadata (&more) - cross-platform!
Algorithmic trading and quantitative trading open source platform to develop trading robots (stock markets, forex, crypto, bitcoins, and options).
Develop Desktop, Embedded, Mobile and WebAssembly apps with C# and XAML. The future of .NET UI
Store securely encrypted backups in the cloud!
One framework for creating powerful cross-platform games.
FlatBuffers: Memory Efficient Serialization Library
”深蓝词库转换“ 一款开源免费的输入法词库转换程序
C# application with primary purpose of farming Steam cards from multiple accounts simultaneously.
mRemoteNG is the next generation of mRemote, open source, tabbed, multi-protocol, remote connections manager.
A C# port of shadowsocks
MIT-licensed, COM-free .NET libraries for creating, reading, editing, converting, rendering, and extracting Office, PDF, email, OneNote, and text formats.
Open-source platform for building cross-platform native Mobile, Web, Desktop, and Embedded apps from a single C#/XAML codebase. Work from any IDE/CLI with Hot Reload, Visual Designer, MCPs, and Skills built for modern .NET workflows. 200M+ NuGet downloads.
Chocolatey - the package manager for Windows
Open-source web application framework for ASP.NET Core! Offers an opinionated architecture to build enterprise software solutions with best practices on top of the .NET. Provides the fundamental infrastructure, cross-cutting-concern implementations, startup templates, application modules, UI themes, tooling and documentation.
EF Core is a modern object-database mapper for .NET. It supports LINQ queries, change tracking, updates, and schema migrations.
QuestPDF is a modern library for PDF document generation. Its fluent C# API lets you design complex layouts with clean, readable code. Create documents using a flexible, component-based approach.
BizHawk is a multi-system emulator written in C#. BizHawk provides nice features for casual gamers such as full screen, and joypad support in addition to full rerecording and debugging tools for all system cores.
Google's Material Design in XAML & WPF, for C# & VB.Net.
Orchard Core is an open-source modular and multi-tenant application framework built with ASP.NET Core, and a content management system (CMS) built on top of that framework.
Powerful .NET library for benchmarking
mal - Make a Lisp
A .NET source generator for generating object mappings. No runtime reflection.
SteamKit2 is a .NET library designed to interoperate with Valve's Steam network. It aims to provide a simple, yet extensible, interface to perform various actions on the network.
Prism is a framework for building loosely coupled, maintainable, and testable XAML applications in WPF, Xamarin Forms, and Uno / Win UI Applications..
Extremely Fast MessagePack Serializer for C#(.NET, .NET Core, Unity, Xamarin). / msgpack.org[C#]
A modern, cross-platform, 2D Graphics library for .NET
A cross-platform .NET library for IMAP, POP3, and SMTP.
Quartz Enterprise Scheduler .NET
:card_index: A simple fake data generator for C#, F#, and VB.NET. Based on and ported from the famed faker.js.
Distributed Application Framework for .NET
Welcome to the home of the Hot Chocolate GraphQL server for .NET, the Strawberry Shake GraphQL client for .NET and Nitro the awesome Monaco based GraphQL IDE.
:angel: The ultimate angle brackets parser library parsing HTML5, MathML, SVG and CSS to construct a DOM based on the official W3C specifications.
Json.NET is a popular high-performance JSON framework for .NET
.NET (WPF and Windows Forms) bindings for the Chromium Embedded Framework
A framework that allows developers to cobble together a better UI for their own WPF applications with minimal effort.
The automatic type-safe REST library for .NET. Refit turns a REST API into a C# interface and generates the HttpClient implementation, with support for HttpClientFactory, pluggable serializers and a testing package.
A pure C# Open Source QR Code implementation
Helix Toolkit is a collection of 3D components for .NET.
A fast, fun and stimulating object to object Mapper
Entitas is a super fast Entity Component System (ECS) Framework specifically made for C# and Unity
Npgsql is the .NET data provider for PostgreSQL.
An installation and update framework for Windows desktop apps
xUnit.net is a free, open source, community-focused unit testing tool for .NET.
Unified Realtime/API framework for .NET platform and Unity.
SharpCompress is a fully managed C# library to deal with many compression types and formats.
ASP.NET Boilerplate - Web Application Framework
The Open Toolkit library is a fast, low-level C# wrapper for OpenGL, OpenAL & OpenCL. It also includes windowing, mouse, keyboard and joystick input and a robust and fast math library, giving you everything you need to write your own renderer or game engine. OpenTK can be used standalone or inside a GUI on Windows, Linux, Mac.
Canonical actor model implementation for .NET with local + distributed actors in C# and F#.
:cake: Cake (C# Make) is a cross platform build automation system.
Microsoft Cognitive Toolkit (CNTK), an open source deep-learning toolkit
The Redis client for .NET
Tools and libraries to glue C/C++ APIs to high-level languages
Cecil is a library to inspect, modify and create .NET programs and libraries.
Incredibly simple real-time web for .NET
C# pure functional programming framework - come and get declarative!
A friendly substitute for .NET mocking libraries.
:bus: Simple and lean service bus implementation for .NET
An easy to use Unity 3D library for creating illustrated Interactive Fiction games and more.
An open-source custom bootstrapper for Roblox Studio that allows you to override files in Roblox Studio's directory, opt into development branches of Roblox, and experiment with Fast Flags.
A .NET GIS solution that is fast and reliable for the .NET platform.
Oqtane is an open-source developer productivity platform for building modern .NET applications and websites that run on Web, Desktop and Mobile.
NLog - Flexible and Structured Logging for various .NET Platforms
An interpreter for the Lua language, written entirely in C# for the .NET, Mono, Xamarin and Unity3D platforms, including handy remote debugger facilities.
A .NET MIME creation and parser library with support for S/MIME, PGP, DKIM, TNEF and Unix mbox spools.
RabbitMQ .NET client for .NET Standard 2.0+ and .NET 4.6.2+
The WPF-based text editor component used in SharpDevelop
Fluent mapping for Dapper, with conventions, immutable object materialization, analyzers, source generators, DI integration, and Dommel support.
SQL query builder, written in c#, helps you build complex queries easily, supports SqlServer, MySql, PostgreSql, Oracle, Sqlite and Firebird
NUnit Framework
A cross-platform plotting library for .NET
Fluent URL builder and testable HTTP client for .NET
Fellow Oak DICOM for .NET, .NET Core, Universal Windows, Android, iOS, Mono and Unity
Confluent's Apache Kafka .NET client
CoreCLR is the runtime for .NET Core. It includes the garbage collector, JIT compiler, primitive data types and low-level classes.
Thoughtfully architected, obscenely fast, thoroughly enjoyable web services for all
This strongly-typed, client library enables working with Elasticsearch. It is the official client maintained and supported by Elastic.
Code analyzer for C# and VB.NET projects
An addictive .NET IoC container
Easy to use F#-like ~discriminated~ unions for C# with exhaustive compile time matching
The .NET MVVM framework for cross-platform solutions, including Android, iOS, MacCatalyst, macOS, tvOS, WPF, WinUI
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 4.7, as well as .NET Core 2.1, .NET Core 3.0, .NET 6, .NET Standard 2.0 and 2.1. Supports the unit test frameworks MSTest2, NUnit3, XUnit2, MSpec, and NSpec3.
All in one email sender for .NET. Supports popular senders (SendGrid, MailGun, etc) and Razor templates.
Theming .NET WinForms, C# or VB.Net, to Google's Material Design Principles.
A GitHub API client library for .NET
A helper library for async/await.
Implementation of Python 3.x for .NET Framework that is built on top of the Dynamic Language Runtime.
Fast and easy to use .NET library that creates or modifies Microsoft Word files without installing Word.
From git log to SemVer in no time
Async/await first CQRS+ES and DDD framework for .NET
C# Websocket Implementation
An asynchronous, collaborative post-exploitation agent powered by Python and .NET's DLR
Official repository - Fully managed, cross platform (Windows, Mac, Linux) .NET library for capturing packets
.NET project templates with batteries included, providing the minimum amount of code required to get you going faster.
Lightweight message bus interface for .NET (pub/sub and request-response) with transport plugins for popular message brokers.
The fastest deep cloning library for .NET – zero-config, works out of the box.
Vim Emulator Plugin for Visual Studio 2015+
GeneticSharp is a fast, extensible, multi-platform and multithreading C# Genetic Algorithm library that simplifies the development of applications using Genetic Algorithms (GAs).
Convert code from C# to VB.NET and vice versa using Roslyn
Pluggable foundation blocks for building distributed apps.