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.
Shlink - A self-hosted URL shortener
Polr - An open source URL shortener. A great non-profit and free alternative to bit.ly, TinyURL, or goo.gl.
Lstu - A nice and open source url shortener. You can use it as service or install it on your own server.
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.
Anonymous URL Shortener - Anonymous URL Shortener, Referer, Anonymizer, Redirection service.