Onni Hakala

Geniem Oy

WordPress plugin which removes all accented characters like <code>åöä</code> from future uploads and has easy wp-cli command for removing accents from current uploads and attachment links from database. 
This helps tremendously with current and future migrations of your site and helps you to avoid strange filename encoding bugs.
Sanitize accents from Cyrillic, German, French, Polish, Spanish, Hungarian, Czech, Greek, Swedish. 
This even removes rare but possible unicode NFD characters from files by using <a href="http://php.net/manual/en/normalizer.normalize.php" rel="nofollow ugc">PHP Normalizer class</a>. These usually happen if you have mounted uploads into your vagrant box in OS-X.
This plugin is wordpress multisite compatible.
More information in github page: https://github.com/devgeniem/wp-sanitize-accented-uploads

WP Sanitize Accented Uploads

Simple plugin which removes accented characters from uploaded files.

Giorgos Sarigiannidis

Remove Uppercase Accents is a WordPress plugin that automatically removes accented characters (currently greek) from elements having their text content uppercase transformed through CSS ( with <code>{ text-transform: uppercase; }</code> ). Currently the script transforms only greek text, but it can be easily extended to support other languages.
Why you would need this: For example, in greek there are accent marks that denote in which syllable you put the stress on when pronouncing a word. However, when words are written in all UPPERCASE, those accent marks are removed. This rule is not followed by the aforementioned CSS rules, as they just use the corresponding uppercase unicode character.
<h4>Features</h4>
<ul>
<li>Automatically removes accented characters from text content uppercase transformed through CSS.</li>
</ul>

Remove Uppercase Accents

Great plugin with a lot of options and extendable!
Great work!

Congrats

Automatically removes accented characters from text content uppercase transformed through CSS.

WP Sanitize Accented Uploads vs Remove Uppercase Accents