My design for the Empress Card for the MLP Tarot deck I just finished. The Empress card is normally associated with birth and renewal so I made use of this to represent Friendship is Magic birth from the previous three generations. The Empress card is also number 3, so I represented the three ponies here in the style of the previous three generations. As well in the show Equestria (and thus Celestia) was founded by the three pony races, so the three ponies also represent the three races here. Celestia symbolizing Gen 4 is made up of all previous generations and 3 pony species.
But 2013 is the 30th Anniversary of My Little Pony, so here is art to honor that milestone.