ringmaster

This plugin performs the simple task of replacing individual author names in feeds with the site name.
This is useful for blogs that are written by multiple authors that have the “authoritative voice” of the blog itself, 
rather than attributing each post to its individual author. This plugin makes the posts in the feeds (all feeds: rss, 
rss2, atom, rdf, etc) appear to be written anonymously, instead using the name of the site as the publishing author, 
rather than the name of the author. This prevents admins from having to edit core files to make posts in the feed anonymous.

Feed Anonymizer

Replaces individual author names in feeds with the site name.

uwcals

Enables WordPress to include thumbnail and custom field data in its RSS2 feed.
How is works:
<ul>
<li>To retrieve post thumbnails: Add “post_thumbnail=1” to your feed’s link. (e.g. “http://www.mywpsite/feed/?post_thumb=1”)</li>
<li>To retrieve custom fields: Add “meta_keys=meta_name1[,meta_name2,meta_name3,…]” to your feed’s link (e.g. “http://www.mywpsite/feed/?meta_keys=post_quote,post_contributor” will retrieve the “post_quote” and “post_contributor” custom fields’ value, if these fields have been added to the post.)</li>
<li>To further customize your feed: use any other WP Feed options, as listed on https://codex.wordpress.org/WordPress_Feeds/.</li>
</ul>
Example: 
The http://news.cals.wisc.edu/feed/?cat=67&post_thumb=1&meta_keys=academic_info will retrieve all posts in category 67, along with their thumbnails (if available) and the value of the ‘academic_info’ field (if available).

UW CALS Extend RSS2 feed

Enables WordPress to include thumbnail and custom-field data in its RSS2 feed

Feed Anonymizer vs UW CALS Extend RSS2 feed