Type A and Type B electrical plugs are the two standard varieties used in the US. Both have two parallel power pins, whereas the latter has an additional grounding pin for safety.

You'll notice that not all electrical plugs are the same and might even have different inserts depending on the country. Here's how many there are.

If you've ever been in the northern US, you may have noticed electrical plugs on cars. These are actually not for charging, but to combat the bitter cold.