Polr - An open source URL shortener. A great non-profit and free alternative to bit.ly, TinyURL, or goo.gl.
adf.ly - Earn money for each visitor to your shortened links with adf.ly!
YOURLS - YOURLS is a website that contains all the tools you need to create and launch your very own URL shortener. URL shorteners like bitly or TinyURL are fine for public use, but they offer limited options in terms of URL customization.
Shorte.st - Smart and easy way to get extra income from your traffic.
Bitly - Get the most out of your social and online marketing efforts. Own, understand and activate your best audience through the power of the link with Bitly Enterprise.
Ouo.io - Link shortener that earns you money for visitors to your links.