Making Pretty Side Bars with css/plugins

Hey guys,

So I have used a lot of plugins while building up my css knowledge base to configure the theme I am using. I now need to work on my side bar and so far the only thing I have done is change background color, make the titles centered etc. But it just doesn't cut it.

So I am wondering if there are any free plugins I can use completely customise the side bar.

Also if you can recommend any good guides out there to customise the side bar, that would be very helpful.

Thank you for answering!!