Wouter Postma

This plugin uses the <a href="https://chrisbracco.com/a-simple-css-tooltip/" rel="nofollow ugc">Simple CSS tooltips</a> by Chris Bracco and a shortcode to create simple tooltips. You can define a link, tooltip location and more in the shortcode.
<ul>
<li><a href="https://profiles.wordpress.org/wouterpostmanl#content-plugins" rel="nofollow ugc">View my other plugins</a></li>
</ul>
To add a tooltip to your website, please install and activate the plugin. 
Then use the shortcode to add a tooltip:
<pre><code>[tooltip text="The tooltip"]The text[/tooltip]
</code></pre>
The above shortcode will add a simple tooltip on top of “The text”. 
If you want to include a link or change the location of the tooltip, this is possible by using the following attributes in your shortcode:
<pre><code>[tooltip text="The tooltip" location="right" href="https://example.com/" rel="nofollow"]The text[/tooltip]
</code></pre>
The location can either be top, right, left or bottom. If you don’t enter a location, the default location (top) will be used. 
As you can see it is also possible to add rel=”nofollow” to your link. 
If you don’t enter a link, the text will link to “#”.

Easy WP Tooltips

Add tooltips to your content easily using a simple shortcode!

Felix W.

Based on the tooltip collection from http://tympanus.net/codrops/2014/10/07/tooltip-styles-inspiration/ this plugin provides different tooltip styles.
You can easily add tooltips by using the small form displayed in the TinyMCE or you manually use the shortcodes.

Tooltip Crazy

Tooltip Crazy adds a new button to the TinyMCE for adding tooltips to your posts and sites via shortcode.

Easy WP Tooltips vs Tooltip Crazy