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.
Wonder Boy! Fata Fury! Discounts! More!
Only available for four days and in Japan
Region Free, indeed
Team Kirby! Mr. Shifty! Jackbox Party Pack 3! Puyo demo! More!
A small wonder