Nigon is the second underground race.

To be honest, I would be happy to encounter harpies, beholder-kin, ifrits, and of course, the Monsters again! But honestly, when it comes to modding, the graphics will be very challenging, I know from experience. And I would advise you to take the manticore out of the neutral faction and put it in Nighon instead of the ifrits, although I also always liked the latter, especially as Anti-Djinn! In general, it will be much easier to rework the manticore than to create new ifrits. But these are just my thoughts. Do as you see fit!