Basically, none. Or none that I know of, or none that is important.
If you are buying something you need to read the details carefully to know what it covers, but whether it is called a "guarantee" or a "warranty" is not any magic legal code word. It's not as if one were good and the other were bad.
In the United States, consumer law is state law so all legal details vary by state. There is also federal consumer law on top of that.
There can be technicalities--for example, you can purchase an "extended warranty" on a car, and here what you are purchasing is not actually a "warranty" at all--it is sort of insurance or service contract that is called an "extended warranty" because its purpose is to extend the real warranty.