There's more to sharpening than just having some abrasive rocks. Like any good hobby, there's a whole swack of accessories to make the experience more fun!
Stone holders and sink bridges keep your knuckles safe and your stones from sliding everywhere.
Honing rods keep your knives sharp and remove burrs, while a leather strop allows you to achieve a god-like polish on your edge. Chromium oxide is like steroids for your strop, it makes your blades even more insanely sharp
A truing stone is an absolute must for keeping your stones flat, and a nagura stone will help you keep your finer stones clean and flat.