Sites like WinWorldPC host abandonware versions of original IBM OS/2 for educational purposes.
If you are hesitant to buy the OS without testing it, consider these official channels: ArcaOS - A Modern Version of IBM's OS/2 (Overview & Demo) arcaos download iso free
If you are using an older version of OS/2 or eComStation, upgrading is highly recommended for modern hardware compatibility. Key features include: UEFI Support: Sites like WinWorldPC host abandonware versions of original