DannyCooper

This plugin removes font-family, font-size, font-weight, line-height and color declarations from existing content.
This can be useful if you have published posts and pages with out of date styling. It also removes unwanted styles that may appear when copy and pasting from Microsoft Word or other text editors.
Before:
<pre><code>Hello world.
</code></pre>
After:
<pre><code>Hello world.
</code></pre>

Font Stripper

Removes inline font declarations from existing content.

Eric Alli

The Google Typography plugins allows you to use any <a href="http://www.google.com/fonts" rel="nofollow ugc">Google Font</a> for any text on your existing website without writing a single line of code. In the Appearance > Typography settings page, simply add and customize as many fonts as you’d like, then apply it to any existing HTML tag or CSS selector.

Google Typography

A simple plugin that lets you use and customize (in real-time!) any fonts from Google Fonts on your existing WordPress site.

Font Stripper vs Google Typography