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.

k0nsl

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 originate from.
For example, this plugin will automatically convert all external links to this format http://anonymizer.mastrcoder.com/index.php?q=http://k0nsl.org/
This produces an anonymous link to k0nsl.org which prevents the original site from appearing as a referrer in the log files of the referred page. This will apply to all external links – except for the ones you decide to exclude.

mastrcoder anonymizer

Anonymize all your external links with the mastrcoder anonymizing service.

Anonymize Links vs mastrcoder anonymizer