I... I modded in genitals, in 40d, then again sometime after 2010 was released after realizing the power of caste-based body definitions. To all creatures.
I also regularly mod in strange or unique creatures. Rock bugs and various mushroom men, cave whales, and various other strange things just for the hell of it.
I even took a list of 'cryptids' from wikipedia and created them in 40d. Haven't updated it for 2010 yet.
On the list of less strange and more awesome mods, I created quite a few various dragonoids. Not generic color-based dragons, but more along the lines of greater/emperor dragons, lesser dragons that are wild animals, feral form of standard dragons that werent supposed to be megabeasts but won't appear otherwise, a basilisk that is severely venomous, but not fire-breathing, and three species of wyvern (flying dragons with wings formed from their forelimbs); the massive mountain wyvern - a light fire breather, a horse-sized species (the most dangerous yet. also a possible mount for sieges.) that is quite vicious and active to make up for it's size and lack of firebreath , and a dwarf-sized relatively tame species that isn't particularly interesting.
Created a bunch of new hostile entities based on kobolds, tigermen, the various semi-megabeasts and trolls, and something I cooked up, all in my sig.