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

fa-tree · Unicode: f1bb · Created: v4.1 · Categories: Web Application Icons

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

fa-tree 
<i class="fa fa-tree"></i>

Looking for more? Check out the examples.