If you read the internet you'll discover more than thirteen unicorn species plus there are actually more than just the pegacorns, pegasi, and unicorns, there are tons of other mythical horse cousins. Showing the easy cousins like the Hippogriff part horse and part eagle would sure be fun, but if the fans want a scene of a hero the dangerous kelpie could be shown in this series, My Little Pony already showed the Kelpie.
I consider the two show equally cute, so if anyone wants to share the species list of mythical horses I'm willing to share the numerous unicorns and even other magical horse cousins. I even know some of the scentific facts of unicorns reading fiction and non-fiction books at the same time.