ran across this a few weeks back:
http://guides.gamercorner.net/ffvi/
(the "Index" tab on the top right has more than just what's featured on the left.)
lots of data, and lots of hyperlinks to bring you to relevant connections. it reminds me of Terii Senshi's FF6 Encyclopedia.
i can't vouch for its accuracy. one problem i noticed is the Metamorph probabilities are wrong; likely based on the estimates in the ancient version of Master ZED's guide. they got tricked by the bogus FF3us Jewel Ring description, so that answers my question of whether it's all automated ROM stat reading.
btw, the "Vulnerability" statistics for monsters are apparently derived by comparing (255 - Defense) and (255 - Mag. Def) to 128.
anyway, it's quite impressive from limited examination. you can click on it all day. while it has Javascript, there's no notable bloat to overcome to get at its piles of information; it worked snappily on this ancient computer.