Ryan Welcher

This is a simple plugin that helps to clean up the admin side of WordPress by only showing the currently logged in user’s content the Post/Page/Media pages.
For the Media list, you can provide a list of user ID’s who’s Media will also be available to logged in users. It is highly recommended to create a user for this purpose.
Credits
This plugin was inspired by an article by <a href="http://premium.wpmudev.org/blog/author/pollyplummer/" rel="nofollow ugc">Sarah Gooding</a> on <a href="http://premium.wpmudev.org/blog/how-to-limit-the-wordpres-posts-screen-to-only-show-authors-their-own-posts/" rel="nofollow ugc">wpmudev</a> and uses portions of that code. Please see the source code for further details.

Restrict User Content

Limits Post/Pages/Media admin screens to only display the current user's content. Media can be shared by providing an ID list.

tavakal4devs

Manage and organize columns in the posts, of custom post types. Not the greatest UI 😁 , but it’s totally free 😘
<blockquote>
<h4>Tavakal – admin columns Features</h4>
<ul>
<li>Change order of the columns (drag and drop).</li>
<li>Support objects,images,text,taxonomy,dates.</li>
<li>We also support nested values.</li>
<li>Sorting by custom fields is supported.</li>
</ul>
</blockquote>

Admin columns

Free powerful plugin to add or customise columns on the administration screens.

Restrict User Content vs Admin columns