Different Types of Tooling

While many tool manufacturers have more extensive answers to this, which you can seek out, here are the basics:

Endmill – used for removing material in a horizontal path, generally has a flat tip

Drill- used for drilling round holes

Ball mill – same as the endmill, but has a round tip. This tool isn't a good choice for making square corners. 

Chamfer tool – endmill shaped with an angled tip

Keyway/dovetail – used to create undercuts

All images from Harvey Tool Company, LLC.