Nintendo Japan has revealed 2 new Pokémon Nintendo 3DS themes: Look Upon the Stars and POKÉMON POP. Each theme costs 200yen. All themes are available for purchase as of June 28th, 2017 on the Japanese Nintendo 3DS eShop store.

Look Upon the Stars

Features: Cosmog and Pikachu with Pokémon constellations in the background. Pikachu is looking through a telescope and the constellations change as the users scrolls.
Music: Sun and Moon OST - Heahea City (Night)

POKÉMON POP

Features: Based off the POKÉMON POP merchandise brand, various Pokémon are shown in various comic style frames.
Music: Sun and Moon OST - Mission in Progress


Source: https://www.nintendo.co.jp/hardware/3ds/theme/index.html