User friendly (css) style insertion plug-in recommendations??

I’m looking for recommendations for a plug-in that will allow the end-user to easily add (or remove) a simple pre-defined CSS class definition to a paragraph, or image, etc in the WYSIWYG editor. I’d build the CSS style definitions for them and include the CSS in the style.css (or similar) to do the groundwork – the plug-in would just need to help the user insert the CSS without dealing with the HTML code/tag behind the scenes. I’m visualizing a drop down like the heading/paragraph box or maybe that box itself having the new styles. They’d also need a way to remove those styles when they go askew, if possible.

Are there specific plug-ins for this that work well for this and don’t leave the user trying to manually hack CSS back out of the tags with it goes slightly off-track? Recommendations appreciated.