Although there are so many of them, it is always good to have more options for social icons as different styled ones can fit better to different websites.
Simple Icons is a set of 96 free social icons that cover almost all of the well-known social services (Twitter, Facebook, Instagram, Google+ and much more).
Related: 50+ Sets of Crisp and Clean Free Icons for Perfect Web Design
All the items are placed on a different background color that matches the related brand and all looking slick. They come in 11 different sizes from 16*16px to 4096 to 4096px and in.PNG format and free to use in commercial projects.
Download Simple Icons - - A Complete Set Of Free Social Icons