ajayver

This plugin gives you the ability to change the appearance of your RSS feed. You can easily add images from custom fields, read more link, category list, tag list and any custom code before or after the feed items. Also, the plugin allows you to delay feed publication for several minutes. It is helpful, when you made some mistake and you will have time to fix it before the post went to RSS and all other services like facebook or twitter.

RSS Manager

This plugin gives you the ability to change the appearance of your RSS feed.

Marvie Pons

Adds the “nofollow” rel attribute to the read more links. No complicated setup. Just activate and everything will work automatically!
Plugin by <a href="http://tutskid.com/" rel="nofollow ugc">TutsKid | WordPress Tutorials, Themes, Plugins, and More!</a>.
<h3>License</h3>
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with WP Nofollow More Links. If not, see <a href="http://www.gnu.org/licenses/" rel="nofollow ugc">http://www.gnu.org/licenses/</a>.

WP Nofollow More Links

Adds the nofollow rel attribute to the more (read more) links.

RSS Manager vs WP Nofollow More Links