Wasn't Lock's Quest a non-RPG strategy game? Never played it, but I watched a full Let's Play of it some time ago.

Well, good thing is that after it was last updated in 2010, that was pretty near the end of the DS' main lifespan anyways.
Once the 3DS launched in 2011, that became Nintendo's main focus.

So we can probably almost just list all the games since:
Etrian Odyssey III, Fossil Fighters Champions, Okamiden(?), Pokemon Black/White/Black 2/White 2, Pokemon Conquest (spinoff, strategy RPG), Shin Megami Tensei Devil Survivor 2, Professor Layton and the Last Spector (I think. Was that the one with the extra RPG included in the US version but cut from the EU version?), Solatorobo, Kingdom Hearts RE:Coded(?), Lufia: Curse of the Gods (action-RPG?).
(the remainder of games being Japanese, but obviously this list is English release only)