A pack of various additional creatures, without any particular theme - essentially a "whatever goes" pack. Aside from many wild creatures and some megabeasts, there are also several races (including the playable Flesh Cult), several additional bogeyman types (most of which have lower skills than vanilla bogeymen, but tend to have additional abilities or other gimmicks), plus additional creatures that will rule over dark pits civilizations.

Credit to Splint and posters on the forum thread for many of the creature ideas.