The best free alternative to TestLink is Klaros-Testmanagement. If that doesn't suit you, our users have ranked more than 10 alternatives to TestLink and eight of them is free so hopefully you can find a suitable replacement. Other interesting free alternatives to TestLink are Kualitee (Freemium), TestBench CS (Freemium), Kiwi TCMS (Freemium, Open Source) and Testpad (Freemium).
Kualitee is your go-to test management tool for test case management, requirements management, test case execution, and Issue tracking. The tool supports both manual and automated testing and third-party integrations.