I got this idea from Musicdevil  please don't hurt me!

Princesses:
Cadence-me
Luna- Musicdevil
Celestia-
Twilight-

More royalty:
Prince Shining Armour-
Fancy pants-
Starlight Wishes(a random character I made up) {Cadence and Shinings Foal}-me

Mane Six
Applejack- CaramelJackDaughter
Fluttershy- Musicdevil
Rainbow Dash-
Rarity- @ElementalStorm000
Pinkie Pie- xX__Cinderblaze__Xx

Arbitrary ponies:
Caramel-CaramelJackDaughter
Sassaflash-
Derpy- me
Doctor Whooves-
Flash Sentry-
Lyra Heartstrings-
Bon Bon-
Cheese Sandwich-

Wonderbolts
Soaring-
Fleetfoot-
Spitfire-

Other Creatures
Spike-
Gilda(hope that's her name)-

I know there are more but my hand's sore...