MrXHellboy

This plugin will provide you a new widget, showing the last modified items. 
You can customize the widget with 5 settings: 
– Title 
– Amount 
– Text between title and date of modification 
– Show the date 
– Post type.
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Last modified items Widget

List your last modified items through a widget. Quick and easy.

freetools

LMP allows you to add in your sidebar a widget that will display the last modified articles in descending order of modification date.
Settings to customize:
<ul>
<li>Allow you to set title widget</li>
<li>Display Number of items</li>
<li>Display modified date</li>
<li>Display thumbnails</li>
</ul>
If no thumbnail was found for the article, LMP will add a generic image.

Last Modified Posts

Add a widget to display the list of the last modified/updated posts.

Last modified items Widget vs Last Modified Posts