A lot of my ponies got new names when I was little. n_n
Glory was Star Streak
Baby Quackers was Ducky
Baby Princess Sparkle was Crystal
Twins Jabber & Jebber were Tipsy and Topsy (I still think these names fit them a lot better!)
Baby Waddles was Flip
Baby Sweet Celebrations was Tufty, Mommie was Comie, and Daddy was Ribbons
Baby Sweetsteps was Tasie
Baby Rattles was Bunny (Tattles was tragically lost. :C )
Twins Puddles and Peeks were Dixie and Trixie
Powder was Powder Puff
High Flyer was Dragonfly
Teeny Tiny Whiskers was Trinket
Baby Cuddles was Rattles
Moondancer, Applejack, Lucky, Firefly, Blossom, Baby Milky Way all kept their original names. I only remember because I wrote them all down in a mini paper pad that somehow miraculously survived all those years!