In no order what so ever and just off the top of my head, if you are lloking for suggestions I could probably do about 50. RPG wise owing to the drought on the DS (and just about everywhere else) I have been playing some of the Japanese backlog of RPGs I never played, while a good bunch I am glad have not been translated I would dain to say at least 50% are of a high quality.
Advance wars 2
Tetris Advance (the Japanese version by minna no soft as opposed to the tetris worlds game)
Eggo mania
Any of the "tactics" games.
Phantasy Star collection, port though it may be it still has PS2.
Megaman Battle Network (any)
Ultimate Brain/Card games
Mr Driller, either 2 or A (2 is action, A is more puzzle based)
Super Robot Taisen (they are all pretty good).