The Kallax Shelf Unit from Ikea is a staple in a lot of people’s homes. It can be stored vertically or horizontally, comes in multiple colors, it’s easy to assemble, and it’s affordable. Once you get the bookcase put together, you have some different options of how to fill that shelving unit up. Storage? Decor? A mix of both?A good rule of thumb for non-ikea inserts is that their dimensions must be 13 in x 13 in or less to fit comfortably. 15in depth should be the max. Here are some ideas for storage.

Here are the options that you can get from Ikea:
KALLAX Hanging organizer for accessories
KALLAX Storage with compartments
Here are some options outside of Ikea:
SONGMICS Set of 6 Storage Cubes Foldable Fabric Drawer Storage Bins Closet Organizer
Beautify Large 6 Tier Clear Acrylic Cosmetic Makeup Cube Organizer
SimpleHouseware Foldable Cube Storage Bin, Beige
Cloth Storage Bins, MaidMAX Set of 6 Nonwoven Foldable Collapsible Organizers Basket Cubes with Dual Plastic Handles for Gift
StorageWorks Cotton Storage Cube Box with Strong Cotton Rope Handle, Waterproof Foldable Basket Bin Organizer, Natural, 3-Pack
Better Homes and Gardens Small Galvanized Bin, Silver
Versatile X Cube Storage Shelf
Versatile H Cube Storage Shelf
DecoBros STACKABLE 3 Tier Desk Document Letter Tray Organizer, Black
File Organizer Mail sorter, With Four Adjustable Dividers Natural Bamboo wood Color