Coin sleeve pages could work better for NDS and N3DS games, but quite frankly, I've never seen the functionality or practicality of storing cartridge-based games this way; you must store them well and handle with utmost care, which I think is overkill. There are small plastic storage boxes that seem like a great and better fit for storing these type of games, I think. But to each their own, as they say.
For me personally, I use
these for GBA games and
these for NDS games. For GB/GBC games they're all in their
cases, stacked neatly on one of my shelves.
I hate gamestop cases.
Mewtwo.
