Rontu

PiwikCounter is a Counter which needs a Piwik installation under your control. Without it, it won’t work. 
It get’s its data through Piwiks API and caches the amount of visits until yesterday and just adds the amount of visits for the actual date.

PiwikCounter

PiwikCounter allows you to show the summary of (unique) visitors as a widget on your blog.

EverPress

Xaver

Mailster Newsletter Plugin

Integrates Piwik Analytics with Mailster Newsletter Plugin to track your clicks
<blockquote>
This Plugin requires <a href="https://mailster.co/?utm_campaign=wporg&utm_source=wordpress.org&utm_medium=readme&utm_term=Piwik+Analytics" rel="nofollow ugc">Mailster Newsletter Plugin for WordPress</a>
</blockquote>
Requires the Mailster Newsletter plugin and the Piwik Analytics tracking code on the website

Mailster Piwik

Integrates Piwik Analytics with Mailster Newsletter Plugin to track your clicks

PiwikCounter vs Mailster Piwik