Empty Coconut Halves
One Horsepower
Feeling a little hoarse
Horseplay
Night-Mare
Shadowfax
Sleipnir
Tesco
Findus
Why the long face?
Neigh You
Torrent
Epona
Binky
Trojan
Llamrei
PegaSUS
BoJack
Amazing Horse
Tastes like Raisins
Agro
Geryon
Ixion
Shadowmere
Ketamine
Ivermectin
Is that a fax that is kept in a dusty dark room?
PegaSUS and Epona are actually already horse names, dont think the others are though
404 Horse Not Found
Test Horse Please Ignore
Whole Horse
Hol Horse
Madam Swish 3:30
Sad Ken
120% Horse
My Kingdom For Horsepower
20% Cooler
Silver Surfer
Ketamine Kevin
Barrell Roll
Secretly a Cheetah (we know which horse this one is)
Morpheus
Erasmus Fry
French Fry
Poutine
Choronzon
The Corinthian
Edit:
2009 Kia Optima
Overage Drinking
Whimsical
Fortunado
Neigh, Thou
Bottemeth Gear
Top Saddle
Leonard Trot-sky
Blazing Burning Saddles
Go on, git!
Schpeed and Power
Big Narf
Jorts
Steven Unicorn
Mayo
HONSE
Not like the other horses
Dead & Beaten
Powered By Apples
Duck Sized Horse
Robot Unicorn
Aqua Teen Hunger Horse
Melancholy
Shergar
Eponavirus (or PONID-21)
Apple Cinder (Ref to Applejack)
Horsing Around
Neigh More Stealin’
Gleaming Shield
Headless Horseless (Ref to Scream Fortress’ boss fight)
Worst Knight Mare
Spare Your Horses
Sunrise Simmer (Ref of Sunset Shimmer)
Princess Molestic (Ref to Friendship is Witchcraft)
Mane Menu
Jolly Roger, Roger! (Ref to Jolly Jumper, Pirates of the Caribbean ride and Star Wars)
Magical Mystery Curse (Ref to the MLP:FiM episode)
She’s a Mane-iac (Ref to Flashdance 80s Dance)