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.

A curated list of awesome open source workflow engines

taskt (pronounced 'tasked' and formely sharpRPA) is free and open-source robotic process automation (rpa) built in C# powered by the .NET Framework

Free Open Source Enterprise Grade RPA

Repository of Windows Workflow Foundation Activities for UiPath Community

WF runtime ported to work on .NET 6

Apache NiFi

A collection of example projects referred to by the Elsa Workflow Guides

A .NET workflows library

Executable workflow elements based on BPMN 2.0