This is an excellent set of Sporting Pictograms that I discovered made by Parutakupiu and stored in Wikimedia Commons. They are Public Domain licensed (CC0), and are therefore available for anyone to use free of any copyright restrictions.
Athletics Button – Demo
Basketball Button Example
Cycling (Mountain Biking)
This work (Sporting Pictograms) is free of known copyright restrictions.
Please be aware that the svg files can be found on Parutakupiu’s area on Wikimedia commons.