TestRail is a popular test case management tool. I would like a TestRail extension for Aha! Develop that provides deep integration between Aha! and TestRail.
Integrate Aha! Develop with TestRail
You can now link features and requirements to test cases and track test runs at the sprint level. Then, track the status without leaving Aha! Develop.
https://www.aha.io/blog/new-aha-develop-testrail-integration