I compiled a list of all mounts that are given names (usually) through supports. I like when this happens, since it implies a strong connection between rider and mount. Or perhaps that you've given a name to the object of your frustrations during years of your knight training. Whatever the case, which one do you think is the best partner? Any criteria will suffice, something the mount does, how great the unit is when riding the mount, or which one you'd personally like to ride into battle. I divided the poll into species because I felt the wyverns are given too much comparative personality in order for horses and pegasi to compete.
Mount name/Rider(Game of origin)
Pegasi
Wyverns
Horses
It's a tough call, but my favorite wyvern is Hyperion. A proud name for a proud creature, and yet the one mention we have of him is in Heath's C support with Priscilla, priceless. For Pegasi, I was considering Belfire. The story of a horse returning home to Cynthia after her mother's death gets me a little choked up...but she loses points for sharing that plot element with Minerva, a mount with much more characterization. I'll instead vote for Huey, the ultimate matchmaker.
It is my grandest hope that we see the return of Fates' petting minigame - but for our mounts. A perfect application if you ask me.