*

Matches any element. (Source: W3C)

HTML:

1. <p>Lorem ipsum dolor sit amet, consectetur</p>
2. <div>Lorem ipsum dolor sit amet, consectetur</div>
3. <blockquote>Lorem ipsum dolor sit amet, consectetur</blockquote>

CSS:

1. *{border:1px solid red}

Output:

In the example, all elements should have a red solid border.