Neo-Queen Serenity

Neo-Queen Serenity  is the former ruler of the 30th Century utopia Crystal Tokyo and the current ruler of the Moon Kingdom.She is the future version of Usagi Tsukino and the mother of Chibiusa.

Appearance
She wears an altered version of the dress she wore as a princess, with a large, wing-shaped bow replacing the smaller one of the princess outfit. She also wears a crown and new earrings. The crescent moon is always visible on her forehead, just as it was with her princess form. Her face and facial expressions are drawn to look more mature than the 20th century Usagi, but her iconic hairstyle is retained

Pretty Soldier Sailor Stellar
Neo-Queen Serenity is only ever shown once in person, when Chibiusa takes the Sailor Senshi to the future. Otherwise, she appears in flashbacks detailing the destruction of Crystal Tokyo.

Magical Star Princess Elyon
In the future, Usagi decided that instead of establishing Crystal Tokyo, she will go back to the Moon and rule it with King Endymion.She's mentioned a couple of times in the short story.

Trivia

 * It is often speculated that Sailor Cosmos is her Senshi form.