Lucy Tomas

This lightweight plugin will display a simple notification bar on the bottom of the page with a button to hide the notification.
<ul>
<li>Possible to add a ‘More Information’ button with a link on it. </li>
<li>All texts, colours and font size can be changed from a simple settings form.</li>
<li>Responsive.</li>
<li>Compatible with Polylang and WPML multilingual plugins</li>
</ul>

Simple Cookie Notification Bar

Displays a simple cookie notification bar on the bottom of the page, customizable colours and texts.

universetech

Want to display a notification about a promotion or a news? Global Notification Bar plugin lets you do that easily.
<h3>Features</h3>
Site manager can easily share any message adding it through the site’s back-end. 
Display important information for customers in a clearly visible header bar. 
Site manager can easily adjust the Notification Bar design. 
Appearance and design of the bar and Content can be freely configurable with HTML and CSS. 
Can be fixed at position (Sticky Bar). 
Set any height you want. 
Colors** are fully customizable. 
Position the bar on top or bottom.

Global Notification Bar

Announcement Bar | Free Shipping Bar | Subscription Bar

Simple Cookie Notification Bar vs Global Notification Bar