brendannee

Keep your site’s content fresh. This plugin adds a box to the WordPress admin dashboard that lists all pages that haven’t been updated in recently. Every time you log in you’ll be able to quickly see which pages might need review to ensure the content is still correct and everything is up to date.
You can set the threshold in days for considering a page “old”, the default is 90 days.

Old Page Reminder

This plugin adds a box to the Wordpress admin dashboard that lists all pages that haven't been updated in 90 days.

Nico

<a href="http://nextgenthemes.com/plugins/regenerate-thumbnails-reminder/" rel="nofollow ugc">Plugin Page</a>
A small reminder in your admin area every time a image setting was changed (in media options, through a theme or plugin)
You most likely want to regenerate the thumbnails after this plugin reminds you to do so, if not already done I suggest you install the most used plugin Regenerate Thumbnails for this. This plugin will offer a redirection to <a href="https://wordpress.org/plugins/regenerate-thumbnails/" rel="ugc">Regenerate Thumbnails</a> in the admins reminder notice, but you can use any other plugin/method you prefer to regenerate thumbnails, just click dismiss when the reminder shows up and then manually navigate to your preferred regenerate plugin.

Regenerate Thumbnails Reminder

Checks if your image sizes have changed or if there was a new one added, if so it reminds you to go regenerate them.

Old Page Reminder vs Regenerate Thumbnails Reminder