Official Bitly plugin for WordPress. Replaces shared links with Bitly short URLs. Also, gives you the option of placing a Bitly widget on your site.
Shorten Link Creator Bit.ly Quick Link Abbreviation Extension
Create tiny urls from your posts with this super easy to use BitLnk plugin for WordPress.
Official iOli® plugin for WordPress. Replaces shared links with iOli Short URLs.
http://bc.vc/ You can create a quick link with the system through the short code API key.