rmtoo - rmtoo is a free and open source requirements management tool.
Azure DevOps - Visual Studio dev tools & services make app development easy for any platform & language. Try our Mac & Windows code editor, IDE, or Azure DevOps for free.
Rational RequisitePro - The list below identifies the supported releases of IBM Rational RequisitePro from which you can select system requirements in different levels and organization of detail.
Helix ALM - Helix ALM is the single, integrated application that lets you centralize and manage requirements, test cases, issues, and other development artifacts and their relationships.
Doorstop - Requirements management using version control.
Visure - Visure offers a flexible , modern and complete requirements ALM Platform (Application Lifecycle Management).