Adam Walter

Admin Notice is a very simple plugin that allows you to display custom notices in the WordPress admin that is visible to all users.
Control over the notice text and styling is available from the plugin’s settings page.
Developers can use the <code>admin_notice_enable</code> hook to control the notice’s visibility on a more granular level. The following example demonstrates how to show the notice only in the “Posts” area of the admin.
<pre><code>add_filter('admin_notice_enable', function($enabled) {

 $screen = get_current_screen();

 if (isset($screen->post_type) && $screen->post_type !== 'post') {
 $enabled = false;
 }

 return $enabled;

}, 10, 1);
</code></pre>

Admin Notice

Nice Plugin!

Display a custom notice to all users in the WordPress admin.

Mark Howells-Mead

Adds a new column to the WordPress admin post list view, containing a preview of the post’s featured image (where available).
<h3>Hooks</h3>
Developers can use the <code>mhm-list-postthumbnail/exclude_posttype</code> filter to exclude the post thumbnail column from certain post types as required. The filter accepts and returns an array.

Add post thumbnail to wp-admin list view

Adds a new column to the WordPress admin post list view, containing a preview of the post's featured image (where available).

Admin Notice vs Add post thumbnail to wp-admin list view