It seems shower caddies can be useful everywhere: Here, Lowe’s had the brilliant idea to use a tension-based shower caddy in the laundry room, used to store your detergent, cleaning supplies, towels, and any other odds and ends needed to keep your house and clothing clean.
Need these! Ikea's Ekby Riset Bracket, allows you to turn the area under your staircase into a useful storage space. The metal bracket can be locked into different angles to support shelving. Could also be used in a pitched attic space.
Storage: Ekby Riset Bracket from Ikea: Remodelista