Off the top of my head...
Resident Evil dropped to $30 new, $20 used
Dropped to $20 new, $15 used
Megaman Battle Network 5 DS
Viewtiful Joe
Dropped to $10 new, $8 used:
Mr. Driller
Dig Dug
Pac Pix
Pac 'n Roll
There are a few more, but I can't remember them...