Quicklook is a great feature of OS X, allowing you to press the spacebar when a file is selected in Finder and quickly look at the contents. If you’re unfamiliar with Quicklook, check out this great introductory article.
As great as this is, there are a few occasions where it would be useful to quicklook a file that is not supported by default. Luckily, Quicklook is extendable with plugins; here are my favorite four.
Read more at The Apple Blog