So far we've only seen third-party download game in the Nintendo 3DS eShop, the decent but could-do-better Let's Golf! 3D. That offering is set to multiply significantly by year's end though, as Nintendo announces the 3DS download games on the way before 2012.
Gotta pre-order em all
Pokemon Sun / Moon demo! Rhythm Paradise! Halloween Discounts! More!
F-Zero X! SEGA 3D Classics Collection! Hyrule Warriors DLC! More!
Grab yourself a bargain
With some extras for My Nintendo members
Disney Magical World 2! Chase Cold Case Investigations! More!
Pokemon Sun and Moon! Beat the Beat! Exile's End! More!
Corpse Party! Just Dance! Gurumin 3D! Discounts and Themes Galore! More!
SHOOT THE BALL, discounts... erm, that's it