AddThis - AddThis free website tools include share buttons, targeting tools and content recommendations help you get more likes, shares and followers and keep them coming back.
Sharingbuttons.io - Quickly generate social sharing buttons with a tiny performance footprint.
ShareButtons.com - ShareButtons.
AddToAny - Share buttons by AddToAny, the universal sharing platform for websites and apps.
Easy Social Share Buttons - Having Easy Social Share Buttons installed into your website is just like having an ultimate solution for the better sharing of your content.
Buffer - Buffer makes it super easy to share any page you're reading. Keep your Buffer topped up and we automagically share them for you through the day.