Most Likely Chord Progressions

Hook Theory is a site which took someone a lot of work, where you pick chords and it tells you the percent likelihood of the chords which follow; check it out here. (Sort of like Markov chains for music?) The only problem is that it's crowdsourced and the crowd so far has been pretty un-metal, two Metallica pieces and nothing else I could find. If you like the site, help them change that!