A top-tier pack includes English-patched versions of Japanese exclusives (e.g., Monster Hunter Portable 3rd or Grand Knights History).
If you only download one collection, aim for the "PSP Essentials v4" pack found on the Internet Archive (uploaded by community user "Redump2"). This specific pack offers:
Avoid any pack that claims "1000+ PSP Games." Over 800 of those will be sports titles from 2005 and Japanese only text adventures that won't boot on your device.
What separates a mediocre ZIP file from a gold-standard collection? Look for these three qualities: