Gombos Robert

Adds the “nofollow” rel attribute to archive links.

Nofollow Archives

Adds the "nofollow" rel attribute to archive links.

jonkemp

Improves your blog’s search engine optimization by “noindexing” pages you choose.
Add the <code>noindex</code> robots meta tag to archives, categories, search pages, tags, author pages, login, admin pages or any other page you choose.
Add the <code>rel="nofollow"</code> attribute to individual pages listed by the <code>wp_list_pages</code> function or the Pages widget. Also, add the <code>rel="nofollow"</code> attribute to archive links, category links, registration and login links.
Changelog
*1.1.2 
**Bug fixes. 
*1.1.1 
**Bug fix where if user did not set nofollow pages, pages links would not display. 
*1.1 
**Added support for nofollowing login and registration links. Also, optimized some of the code. 
* 1.0 
**Added support for nofollowing individual pages in <code>wp_list_pages</code> function. 
* 0.5

Ultimate Noindex Nofollow Tool

Improves your blog's search engine optimization by "noindexing" pages you choose.

Nofollow Archives vs Ultimate Noindex Nofollow Tool