TIEro

This plugin is now available as part of <a href="https://wordpress.org/plugins/tietools-automatic-maintenance-kit/" title="TIEtools" rel="ugc">TIEtools</a>, which also includes post expiry and server log file removal.
A simple duplicate post deletion plugin. Spots posts with the same title and removes all but one of each.
<ul>
<li>Checks in published, draft, pending and private posts on demand</li>
<li>Includes or excludes user-defined list of categories</li>
<li>Moves all duplicate posts to the Trash (leaving the oldest or newest original copy)</li>
<li>Permanent post deletion is handled by WP’s built-in Trash removal</li>
<li>Power button to switch everything on and off without messing with the plugins page</li>
</ul>

TIEdupedeleter Simple Duplicate Post Deleter

Simple duplicate post deleter. Trashes duplicate posts based on status and category. Keeps newest or oldest original copy.

Ruhul

This plugin offers a few lightweight features to speed up your WordPress site without much hassle.
<h4>Far Future Expiry</h4>
When the feature is enabled, this plugin will modify your .htaccess file by inserting code which will add expires headers for common static file types.
Expiry header specifies a time far enough in the future so that browsers won’t try to re-fetch images, CSS, javascript etc files that haven’t changed (this reduces the number of HTTP requests) and hence the performance improvement on subsequent page views.
<h4>Gzip Compression</h4>
You can also enable Gzip compression on your site using this plugin. Gzip compression will speed up your WordPress site by compressing the page output and sending it to your visitors browser.
When enabled, the plugin will do gzip compression if the visitor’s browser can handle it.
This feature may conflict with a few other plugins. So disable this feature if you need to use a plugin which doesn’t work with gzip compression.
<h3>Usage</h3>
To use this plugin do the following:
1) Ensure that the “mod_expires” module is enabled from your host’s main configuration file
2) Check with your hosting provider or if you have access to the httpd.conf file the following line should be uncommented: 
LoadModule expires_module modules/mod_expires.so
3) Enable the “Far Future Expiration” checkbox
4) Set the number of days till expiry
5) Select the file types you wish to enable the “far future expiration” feature for by using the checkboxes in the “File Types” section
NOTE: When you use this plugin, the file selected file types are cached in the browser until they expire. Therefore you should not use this on files that change frequently.
More details can be found on the <a href="https://www.tipsandtricks-hq.com/wordpress-far-future-expiration-plugin-5980" rel="nofollow ugc">plugin’s documentation page</a>

Far Future Expiry Header

This plugin will add a far future expiry header for various file types to improve page load speed of your site

TIEdupedeleter Simple Duplicate Post Deleter vs Far Future Expiry Header