Well, something Good about the GSL...

[pawsplay]

A fan-made index that is not for sale is bound to be all right - if nothing else because it is fair use.

Lists are not copyrightable anyway. WotC can claim the individual items (those that are trademarkable, anyway), but then the list publisher could say, "This is a reference."

 

[Grazzt]

Because if there is a second, third, whatever print run of the MM and the Orcs are moved one page back due to errata, someone could say "Well this D&D compatible product says page 201, but they are on page 202. Lousy quality control! Won't buy again! *nerdrage*"

Just do like WotC did in a few places in the 4e books... "page XX"