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.
Shareaholic - Shareaholic is trusted by over 300000 brands, businesses, agencies, and individuals to grow website traffic and engagement 24 hours a day, 7 days a week.
AddToAny - Share buttons by AddToAny, the universal sharing platform for websites and apps.
Crazy Egg - Through Crazy Egg's heat map and scroll map reports you can get an understanding of how your visitors engage with your website so you can boost your conversion rates.
Simple Share Buttons - SimpleShareButtons is a plug-in for WordPress that comes with eleven different social sharing button sets.