GitHub is a platform for code, scripts, and documentation. You will not find a valid, unused, perpetual vCenter 7 Enterprise Plus license key in a public GitHub repository. What you might find:
If a key is revoked, your vCenter server may lose management functionality, halting automated backups, DRS balancing, and central monitoring. Compliance and Auditing Liabilities Vcenter 7 Enterprise Plus License Key Github - Google
This example doesn't cover actual license key management due to the reasons mentioned. GitHub is a platform for code, scripts, and documentation