Schalk Burger

You can use this plugin to prevent your site from appearing in the server logs of referred pages as a referrer. The operators of the referred pages cannot see where their visitors come from any more.
For example, this plugin will automatically convert all external links to this format
https://href.li/?http://example.com/
This is an anonymous link to example.com which prevents the original site from appearing as a referrer in the log files of the referred page.
Plugin based on the WP Blank Referer by blackhatzen.

Anonymize Links

Anonymize all your external links with the href.li service.

Hansdeboeck

You can use this plugin to prevent your site from appearing in the server logs of referred pages as a referrer. The operators of the referred pages cannot see where their visitors come from any more.
For example, this plugin will automatically convert all external links to this format http://cube.hacemedia.be/url/?http://example.com.
This is an anonymous link to example.com which prevents the original site from appearing as a referrer in the log files of the referred page.
Information:
Reliability Hide the referrer from linked sites ? the ?Referer? header will always be blank.
Speed No waiting pages ? no slowdown.
No Ads Links are free of advertisements.
Security All traffic is encrypted using SSL.
(Based on the WP Blank Referer by blackhatzen)

Anonymize Cube

Anonymize all your external links with the Cube service.

Anonymize Links vs Anonymize Cube