This service allows your visitors to vote for your website. It is easy to integrate the service into your web pages. There is no own webspace needed. Where’s the difference? The difference to other voting services is that every user can vote. The users do not need an account to submit their votes.

WP Topvotes

This Plugin let the visitor vote your site via a simple widget like the facebook "I like this" button.

natekinkead

This simple yet powerful plugin integrates with the bbPress forum plugin to add a new feature which allows users or visitors to vote up or down on topics and replies. Each topic and reply has a total score with an up arrow and a down arrow.
This plugin uses AJAX to save the vote on-the-fly without refreshing the page.
It’s also AMP compatible!
Visitors can only vote once on each topic or reply.
Features Included: 
* Show or hide (and customize) labels for up and down 
* Disable voting on topics or replies globally 
* Disable voting on specific forums 
* View-only score on closed topics 
* Sort topics and replies by voting scores 
* Admin bypass 
* GamiPress integration
Pro Features Available: 
* Historical weighted score visualization 
* Accepted answers 
* “Who voted” avatars 
* Sort dropdown 
* Sort on weighted score 
* Sort on trending score 
* Trending topics widget 
* Schema for Q&A rich snippets 
* Voting email notification to author 
* Mark topics or replies with poor scores as spam
Purchase bbPress Voting Pro at <a href="https://wpforthewin.com/product/bbpress-voting-pro/" rel="nofollow ugc">WP For The Win</a>!

bbPress Voting

I hope you enjoy this plugin!  If you have any questions, please post a topic in the for support forum.

Couldn't believe there was nothing out there like this!

Although I wish it had some options for placement. Not sure I like it above the author avatar.

Pretty cool

Let visitors vote up and down on bbPress topics and replies just like Reddit or Stack Overflow!

WP Topvotes vs bbPress Voting