Robin is an open source emulation front end. There are better front ends--but probably not better databases. Robin includes a database that pulls together MAME, Datomatic/No Intro, OpenDB, GiantBomb, LaunchBox, and GamesDB. This can be updated easily in the GUI, and Robin will pull artwork from any or all of these sites as it is available. Robin prefers to pull from sites that distinguish between regions, since artwork by region can be different.

Robin will sort through your ROMS and pull out only the good ones, leaving behind the dupes and hacks. It then will present them to you as games, grouping the nearly identical versions of ROMs so that you can see through the mountains of crap.

About 26k ROMS boil down to 13k games. Of these, 11.9k are non-crap, playable video games.

The database includes flags for Crap Adult Unlicensed MESS mechanical User rating (your rating) Beaten (by you) Playable

Most of the crap and unplayable have already been marked. But the GUI has tools to keep marking them and save to the database.

Robin also has some wicked-fast filters on all the common metadata, so you can find the best version of the game you want to play pretty fast.

Development has more or less stopped, because the work is too much for one person, and it was just too time consuming. But the database is valuable and I wish somebody would make use of it. Please let me know in the issues if you do find a use.