If you already own a collection of PS2 ISOs (ripped from your personal discs), converting them to CHD is a one-way ticket to reclaiming hard drive space.
If you find an emulator or hardware (like an ODE for a real PS2 console) that does not support CHD, you can revert the file back to its original ISO format losslessly: ps2 chd roms full
Finding a pre-compressed "full set" often leads to community-maintained repositories rather than standard commercial sites: If you already own a collection of PS2
Popular emulators like PCSX2 can run PS2 games. PCSX2 supports CHD files, making it a convenient choice. making it a convenient choice.