Take your icon game to the next level. Check out Fonticons, from the maker of Font Awesome.
             

fa-plus-square · Unicode: f0fe · Created: v3.0 · Categories: Medical Icons, Web Application Icons, Form Control Icons

After you get up and running, you can place Font Awesome icons just about anywhere with the <i> tag:

fa-plus-square
<i class="fa fa-plus-square"></i>

Looking for more? Check out the examples.