provides customizable pop-up alerts for hundreds of Mac apps, making sure you never miss an important chat message or completed download. You can use Growl to set an alert for just about anything, and you can also make Growl notifications look practically any way you want. The built-in themes and the list on the official Growl Styles page
don't even begin to cover all the options for gorgeous notifications, from the minimal to the very flashy.
Here are 10 lesser-known Growl styles that look a lot nicer than the defaults: