It might have been wrong to refer to a cheat sheet in high school calculus class, but nobody is going to blame you for not being able to identify all of the various types of fasteners, screw heads, drive types, nut and washer styles available today.
I ran into this Fastener Type Chart created by Bolt Depot while trying to identify a mystery drive shape used to fasten a part I wanted to remove from a home office task chair (the extraneous piece kept hitting the wall in a narrow space). I've learned it's advisable to know the proper name of a part beyond referring to it as a "whatchamacallit" or "thingy" before heading out to the local hardware store while hunting a corresponding tool, and this sheet is an easy visual reference for identification purposes.
If you feel like revisiting those high school years and testing your identification prowess, there's even a printable PDF version available here. Better yet, load up the image to keep on your smartphone, so you'll always have it to refer to while shopping for home improvement projects.
(Images: Gregory Han; Bolt Depot)