VMware offers a "Free Edition" of ESXi. While it has some limitations (such as a maximum of 8 vCPUs per virtual machine and no central management via vCenter), it is a fully legal, perpetual license.
frequently share methods for licensing these older versions for lab and home use. Licensing Options for ESXi 6.5 esxi 65 license key github exclusive
Community members often maintain lists of keys for homelab and educational use: hegdepavankumar/VMware-ESXi-License-Keys VMware offers a "Free Edition" of ESXi
The Risks of Using "ESXi 6.5 License Key GitHub Exclusive" Links it is a fully legal