The Nightsteed was from the Lost Desert, maybe something along that line?
![Image](http://images.neopets.com/items/seti_faerie.gif)
Faerie Seti
![Image](http://images.neopets.com/items/scarabug_fire.gif)
Fire Scarabug
![Image](http://images.neopets.com/items/dua_fire.gif)
Fire Dua
![Image](http://images.neopets.com/items/seti_fire.gif)
Fire Seti
Maybe a zombie?
![Image](http://images.neopets.com/items/anubis_zombie.gif)
Zombie Anubis
![Image](http://images.neopets.com/items/kepru_zombie.gif)
Zombie Kepru
![Image](http://images.neopets.com/items/mauket_zombie.gif)
Zombie Mauket
![Image](http://images.neopets.com/items/scarypet_twister_wrap.gif)
Mummy Baby
Not a lot of equine petpets, but some similar quadrupeds:
![Image](http://images.neopets.com/items/gpp_vacana.gif)
Vacana
![Image](http://images.neopets.com/items/petpet_des_nuk.gif)
Nuk
![Image](http://images.neopets.com/items/palamoose.gif)
Dofrey
![Image](http://images.neopets.com/items/bosu_red.gif)
Blurgah
![Image](http://images.neopets.com/items/pet_winter_4.gif)
Bika
![Image](http://images.neopets.com/items/pet_des_8.gif)
Apis
![Image](http://images.neopets.com/items/petpet_fangy.gif)
Fangy
Pestilence related:
![Image](http://images.neopets.com/items/boogie.gif)
Bogie (snotty!)
![Image](http://images.neopets.com/items/petpet_chumablah.gif)
Chumablah (A stretch, but seems like it'd spread death)
![Image](http://images.neopets.com/items/med_petpet_1.gif)
Crokabek (ravens/crows seen as harbingers of death)
![Image](http://images.neopets.com/items/pets_flightning_bug.gif)
Flightning Bug (flies spread many diseases)
![Image](http://images.neopets.com/items/manger_green.gif)
Manjeer (already looks like he has a pestilence)