A pony’s name is usually something catchy, and usually reflects the pony’s personality and special abilities. When creating a pony, sometimes it’s best to start with the personality and abilities, then come up with a suitable name.

Some examples:

Twilight Sparkle
Applejack
Rainbow Dash
Rarity
Fluttershy
Pinkie Pie
Shining Armor
Big Macintosh
Derpy Hooves