uepselon

This plugin offers your blog visitors a <a href="http://www.foxload.com/firefox-download/" title="firefox download" rel="nofollow ugc">firefox download</a> button in different formats and colors on the sidebar.
Different banner formats and colors are included. The plugin use the wordpress locale settings for proper language versions of firefox.
You can place firefox buttons as widget and if your theme does not support widgets, you can place this <code><?php if(function_exists('get_foxload_button'))get_foxload_button(); ?></code> php code at the preferred position in your template.

Foxload Firefox Download

Offers your blog visitors a firefox download button in different formats and colors on the sidebar.

Demetrius Tautu

This plugin allows your visitors to subscribe to your push notifications as well as receive push notifications whenever you publish a new post.
The process of subscription is 100% automated and your subscribers will be saved within your DigitalPUSH account.
The process of sending notifications on a new post is also 100% automated and it will notify all your previously subscribed users with the following information: 
* Post title ( up to 64 characters ) 
* Post content without any HTML tags ( up to 128 characters ) 
* Post permalink 
* Post featured image ( If the post has no featured image, a standard bell image will be used instead. The same applies if your featured image is http:// instead of https:// )
The subscription is made by implementing the DigitalPUSH javascript library into your pages ( https://cdn.digitalpush.org/lib.js ), library which handles the entire process. 
The push notification sending process is handled by making a POST call from the plugin to the DigitalPUSH API ( https://api.digitalpush.org/push/ ).
To make use of the plugin you will need an account with DigitalPUSH which can be created here: https://digitalpush.org/register.php 
The registration is instant and completely free.
DigitalPUSH is a free to use push notifications service which can be found here: https://digitalpush.org 
DigitalPUSH terms of service: https://digitalpush.org/tos.php 
DigitalPUSH privacy policy: https://digitalpush.org/privacy.php

DigitalPUSH notifications

This plugin allows you to to implement push notifications with your WordPress blog.

Foxload Firefox Download vs DigitalPUSH notifications