9gaurav

A cool , simple sidebar widget for Google Plus profile badge. 
Displays your Google+ profile pic, short information and link to your Google+ profile.

Google+ Badge

A Google+ Badge displays your profile information for your blog or site.

Alex Sawallich

This plugins enables the famous Google +1-button in your wordpress-installation. The button is shown beneath 
your posts/pages. With this button you can share the permalink to your post/page in your Google+ profile.
You’ve got the possibility to change the look of the button in the same manner, that you can do by using the 
configurator that Google provides: see <a href="http://www.google.com/webmasters/+1/button/" rel="nofollow ugc">Google plus one</a>.

Google+ One Button

Provides a +1 button from Google+ beneath each post/page.

Google+ Badge vs Google+ One Button