Interesting Symbols You Can Type On Your Keyboard But Never Use

± 'The plus-minus sign is a mathematical symbol commonly used to indicate the precision of an approximation, or as a convenient shorthand for a quantity which has two possible values opposite in sign.'

§ 'The section sign is a typographical character used mainly to refer to a particular section of a document, such as a legal code.'

^ 'Caret, sometimes spelled phonetically, Carat, is used by an author or editor to indicate where something is to be inserted into a text.'

{ } 'Curly brackets (also called braces) are sometimes used in prose to indicate a series of equal choices: “Select your animal {goat, sheep, cow, horse} and follow me”.'

~ 'The tilde is a mark placed over a letter to indicate a change in pronunciation.'

| 'The vertical bar has various names including the pipe, verti-bar, vbar, vertical line, vertical slash, or divider line by others. It has various usages in mathematics, where it can be used to represent absolute value, among others; computing and programming; and general typography, as a divider not unlike the interpunct.'

Definitions via Wikipedia. Where else?