Pullblox (Pushmo in America), Fallblox (sequel to Pullblox) (Crashmo in America), Pokémon Dream Radar (Pokémon AR Searcher in Japan), Dasshutsu! Zombie City, and HarmoKnight are recommended, out of what I have on my 3DS.
Note that Zombie City is currently only available in Japan.
HarmoKnight is going to be released in March 2013, though.
If you have Pokémon Black 2 Version and/or Pokémon White 2 Version, definitely get Pokémon Dream Radar.
Just to give you an idea on how the 'more unknown' games are like.