Mind Flayers?

[kenobi65]

A couple early d20 modules had mind flayers in it when everybody was working under the draft srd (which included mind flayers) and the gentlemen's agreement, it wasn't until the full srd was released more than a year after 3e released that mind flayers were specifically not allowed anymore without explicit separate permission.

Living Dragonstar had set up mind flayers as the campaign's BBEGs, until Fantasy Flight discovered that they didn't wind up in the final SRD, and so, they had to shift course on the campaign arc to set up some new BBEGs.