There are so many threads about inventory management, and things like the Stickerbook and the Furnishing Vault have been very helpful, but more can be done. What if players had the option to turn Sentimental items into Collectibles? It would have it's own category and each item converted would have a little description about what the item is and where it came from. This way the player would free up space without losing the memory.
I don't know how this could be accomplished. Maybe the player could put their own description about the item. But I feel this would help a lot of players free up inventory space without losing things that are valuable to them.