I was playing my picross game earlier and I went to download more puzzles to play. But apparently there's a limited number of puzzles that can fit on the actual game cart. Is there like a "download puzzle pack" or something that I can put onto cyclods so I can have all the puzzles at once? (obviously this would involve me putting picross ds on the cyclods, as well, but obviously that's not a problem)

 

Or I suppose you could create multiple saves. I know the Acekard supports this by default (can select something like game1.sav, game2.sav, etc) but you could also do it manually.

...as if Picross didn't have enough puzzles. Try moving on to the older Gameboy ones if you're really finished with it.