As of version 1.17 , the popular PPSSPP emulator natively supports CHD files, making it the new gold standard for digital collections. How to Use These Files
Look for collections uploaded by users like RetroRoms or Vimm’s Lair (mirror). The best sets include a .dat file for RomVault. psp chd internet archive better
psp-chd-zstd-redump-part1 directory listing - Internet Archive As of version 1