Here are some facts about Lilac Sky:

• She is the fifth pony to have “Lilac” somewhere in her name, following Lyrica Lilac, Lilac Links, Lilac Hearts, and Lilac Luster.
• She and Sky Sweeper are the second ponies, and the first two female, who have “Sky” somewhere in their name, after Twilight Sky.
• She and Spring Step are the fifth Pegasus ponies to have Tabitha St. Germain as the their voice actresses, following the Shadowbolt mare, Doctor Hooves and Meadow Song (all from Season 1), and Wild Fire (Season 2).

You can find more facts about her here, along with her partner, Spring Step