I was looking through the Certified stuffs and figured to throw some attention at the Spam fighting stuff as it's generally a hot topic. 

One of my favorite things to use on my own sites with any script is Project Honeypot. It's made by the same folks that made Cloudflare (it was actually here first and they expanded to create Cloudflare. Interesting story there. https://www.cloudflare.com/our-story/ )

So I was pleased to see WebHive add a Project Honeypot plugin.

Another tool is to let other sites handle the actual verification and use that via Social Login tools. There are a few:

https://www.socialengine.com/marketplace/app/social-login-and-sign-up-plugin

https://www.socialengine.com/marketplace/app/social-media-login-plugin

Using a verification tool can be helpful:

https://www.socialengine.com/marketplace/app/two-step-verification-plugin

https://www.socialengine.com/marketplace/app/one-time-password-otp-plugin

Or, have your members verify other members:

https://www.socialengine.com/marketplace/app/members-verification-by-other-members-plugin

https://www.socialengine.com/marketplace/app/members-verification-plugin

You can see there are quite a few plugins. Hopefully, I didn't miss any. Don't forget the built in reCAPTCHA too! There are also other ways built in to the SocialEngine script to help with spam prevention.