Based on multiple studies, the most popular social networks are : Facebook, Twitter and Google+, and they are proved to improve rankings.
There are 3 types of Social Toolbars :
Content Top / Bottom Toolbar
Content Left / Right Toolbar
You can enable / disable the toolbar, setup where to display it (homepage, post pages, custom taxonomies and so on), setup a background color, toolbar position (horizontal & vertical) & custom margins.
You can also choose from a list of buttons what social media buttons to display, the button size (big or normal) & if you wish to display a counter or not.
Small Buttons with counter