Kaspars

Metronet AS

Plugin adds a meta box to every post, page and custom post type where users with editor capabilities can promote other users (with author or contributor capabilities, by default) as editors of that post.
Plugin provides the following filters:
<ul>
<li><code>custom_editors_enable_roles</code> — Specify an array of user roles which should be allowed to be promoted as editors of specific posts and pages. The default is: <code>array( 'contributor', 'author' )</code>.</li>
</ul>
A plugin by <a href="http://metronet.no" rel="nofollow ugc">Metronet</a>.

Multiple Editors

Allow multiple editors and contributors per post or page. Also enable contributors and authors to upload files and add new pages by default.

Mstoic Themes

This plugins enables media uploads by contributors. By default, contributors can not upload media files, this plugin allows them to do just that.

Multiple Editors vs Contributors Media Upload by Mstoic