A "full" set contains hundreds of clones and adult games. Use tools like Simple Arcade Multifilter to curate your ROM library to only include games you want to play.

: Another reliable archive containing the full romset. Key Ingredients for a Complete Set

A "Full Reference Set" means the collection contains every single game supported by that specific emulator core version, including all parents, clones, BIOS files, and sometimes CHD (Compressed Hunks of Data) files for disc-based arcade games. Why Choose a Non-Merged Set for MAME 2003-Plus?