Some forums share real keys from old versions, but:
Searching for free keys often leads to "warez" sites that bundle software with malicious code. Since ADB AppControl requires to be active on your phone, a compromised version of the app could: Adb App Control Activation Key Free
You can get a key by making a small donation (roughly $7 USD) on the Official ADB AppControl site . This is a one-time key for personal use on one PC. Some forums share real keys from old versions,