Sparanoid

Adds readability.com widget on your site. A must-have plugin if you’re a Readability publisher. This plugin also works fine with multisite enabled WordPress (aka. WordPress Mu).
More information please visit my <a href="http://sparanoid.com/work/readability/" rel="nofollow ugc">site</a>.

Readability Buttons (readability.com)

Adds readability.com widget on your site.

Unfluff.io

Tired of low-quality content? Unfluff it. 
Quality content that keeps your readership engaged needs to do more than just reach a certain word count. 
Unfluff helps keep your content on-point and easily readable, can detect AI-written content, and keeps your content team accountable. 
And, it’s 100% free.

Unfluff.io – Content Optimization

Unfluff helps keep your content on-point and easily readable, can detect fluff/filler and AI-written content, and keeps your content team accountable.

Readability Buttons (readability.com) vs Unfluff.io – Content Optimization