Legal Disclaimer: MAME is an emulator, but ROMs contain copyrighted code. This article is for educational purposes regarding digital preservation. You should only download ROMs for games you physically own, or utilize public domain/abandonware where legal.
If you are a collector or preservationist, the "top" packs are not found via Google search results (which are full of malware). Instead, they live in the "Arcade Preservation" ecosystem: all mame roms pack top
If you still wish to proceed, here are some general tips: Legal Disclaimer: MAME is an emulator, but ROMs
A true top pack follows the latest MAME version (e.g., 0.271 or newer). It includes: No missing dependencies
No missing dependencies. No broken missing CHD errors.