An assortment of chisels should be part of every workbench. Chisels are not just for wood carvers. Any woodworker will need chisels to clean out joints and saw cuts. Look for chisels made of high-alloy carbon steel or chromium-vanadium alloyed steel. Hardwood grips are best, especially if they have metal caps on them. This will keep the end of the handle from becoming malformed when you hammer on it.
It's important to sketch out a plan in advance so you don't have to take a sudden trip to the store. Sometimes, no matter how much you plan, you still end up needing a part. A lot of craftspeople keep a basic stock of supplies on hand just in case. Also, as you get more experienced at crafting, you gain a better understanding of what you need for a project.