Top Welcoming Open-Source C# Repositories

the subtitle editor :)

PnP PowerShell

A simple app for tracking monthly spending and working towards financial goals.

Cross-platform 2D game engine focused on ultimate productivity built in .NET

A native .NET LLM inference engine for GGUF models. TensorSharp provides a console application, a web-based chatbot interface, and Ollama/OpenAI-compatible HTTP APIs for programmatic access. It supports Windows/MacOS/Linux with full GPU capability

Open source collaborative projects driven by the NefMoto.com community

A collection of code samples for the Uno Platform

Free, open-source SQL Server performance monitoring — 32 collectors, real-time alerts, graphical plan viewer, MCP server for AI analysis. Supports SQL 2016-2025, Azure SQL, AWS RDS.

:angel: Extends AngleSharp with a .NET-based JavaScript engine.

C# application to switch default playing device. Download: https://soundswitch.aaflalo.me/

Flexible layout tool for creating UI on any platform

The Seq command-line client. Administer, log, ingest, search, from any OS.

Create text adventure games

Self-hosted optimization, monitoring (NMS), and security audit tool for UniFi Networks. Includes Wi-Fi Optimizer for wireless health scoring and channel optimization, advanced DNS/VLAN/firewall security checks, config optimization suggestions, centralized WAN and LAN speed test server w/ L2 tracing, CM, ONT, SFP, 5G modem stats +more.​​​​​​​​​​​​​

The original unitystation

An update to Component factory's krypton toolkit to support .NET Framework 4.6.2 - 4.8.1 to .NET 8 - 10

Future version of MCSL, a brand new server management tool. Redefined, Versatile, Easy to use. (WPF Launcher & Daemon)

A collection of accessible, headless primitives and beautifully-designed components for Blazor inspired by shadcn/ui.

A 2D game engine with its own programming language and IDE.

A geospatial library for .NET

Quartz Enterprise Scheduler .NET

Blog system of https://edi.wang

Sekiban - an Opinionated Event Sourcing and CQRS Framework using C#. It can store data into Azure Cosmos DB, AWS Dynamo DB or Postgres

An embeddable C#/.NET AI agent runtime for building extensible agents that evolve with your projects.

Simple, secure, reliable agents. Self-hosted. Open source. Built with .NET.

Project Homepage & Forums

Utility to optimize media files for Direct Play in Plex, Emby, Jellyfin, etc.

A modern spotnet client and index for your *arr apps.

NUnit 3.0 Visual Studio test adapter for use under VS 2012 or later

The presentation framework for .NET MAUI.

”Open棟梁”は、長年の.NETアプリケーション開発実績にて蓄積したノウハウに基づき開発した.NET用アプリケーション フレームワークです。 (”OpenTouryo” , is an application framework for .NET which was developed using the accumulated know-how with a long track record in .NET application development.)

A powerful open-source tool for managing networks and troubleshooting network problems!

This library for DotNet Aspire enables poly repo support and the addition of Git repositories to your Aspire projects. It simplifies multi-repository management and streamlines dependency handling, making it easier to work with multiple repositories in a Aspire project.

FFXIV Dialogue text translator

The Agentic Software Factory

Modern C# bindings and native NuGet packages for SDL3 and its companion libraries.

ParquetSharp is a .NET library for reading and writing Apache Parquet files.

All in one .wz file/map editor for MapleStory game files

Process Multiple Asynchronous Tasks in Various Ways - One at a time / Batched / Rate limited / Concurrently

Easily access public holidays for 200+ countries via .NET, REST API, Docker, or NuGet for online and offline use.

Open-source cross-platform symbolic algebra library for C# and F#. Can be used for both production and research purposes.

Lightweight runtime performance diagnostics and agent-readable profiling for Unity 6 URP+HDRP (FPS meter).

Free Bootstrap 5 components for ASP.NET Blazor + optional enterprise-level stack for Blazor development (gRPC code-first, layered architecture, localization, auth, ...)

Mailozaurr is a PowerShell module that aims to provide SMTP, POP3, IMAP and probably some other ways to interact with Email. Underneath it uses MimeKit and MailKit libraries written by Jeffrey Stedfast.

Remote Procedure Calls for Kerbal Space Program

GSharp Programming Language

KNI is a cross-platform C# game framework.

PowerPoint .NET library for reading, modifying, and generating PPTX presentations without Microsoft Office

GHOSTS (General Human-Oriented Synthetic Teammates and Systems) is a realistic user simulation framework for cyber experimentation, simulation, training, and exercise