1. Anything you don't regularly that is reorderable, sell it, if you have some kind of sets etc. just note down what you sold so you can quickly reference what you used to have, and buy it again when the need arises
2. Extra characters, if you're into collecting furniture sets particularly those you can't reorder such as the Sloppy series, then showcase it in the extra character's house, then you have extra space in their closet.
3. Museum exhibits
4. Buy new stationary, write the item name on it that you wanna store, put the item in the letter, and save the letter in post office, then when you want it, you go to your stored letter, and you can quickly read what item is in the letter, and the letter out if it's the right one
5. Others have mentioned the beach
6. Another game cartridge if it ever got that serious
