In my previous job we used TestLink.
You can manage requirements and test cases, both can be organised in folders or test suites.
TestLink automatically assigns a unique intern number to test cases, which can be used for cross references and for the requirement coverage. It has great options for reporting, but I’m not sure about generating reports based on custom fields.
Test cases can have a status, like draft, or final.
You can have a separate test plan for the regression testing and then create reports from this test plan.
The reports didn’t include the fact, that some test cases were executed more than once. That was great for the overall coverage, but sometimes, we wanted an overview, how many testcase executions were done alltogether for a project, and it was really difficult to get that number.
TestLink is opensource, but it seems that it’s no longer developed and maintained. 
We’ve been looking for alternatives, and among others we came across Klaros and TestMonitor, which seemed quite useful. But except from a few experiments with their free trials, I don’t have any practical experiences.