I'm currently using an SD card reader with my router (pictured above), so I can quickly share any pictures I take with my camera across the network. Check with the router manual to find out if there are any storage limits. Older routers may not be compatible with larger storage drives, but with newer models, you can typically use anything from a small flash drive to a 5TB (or larger) external HDD will work. You can choose just about any type of USB storage drive to add to your network. Here's how to set up a networked hard drive with a Mac. Setup is easy, but if you have a Mac, you'll need a different set of instructions than PC users. Maybe you want to share documents with coworkers without having to upload everything to Dropbox or share music files with the entire family.
Setting up a networked hard drive is a great way to access all your files from multiple computers.