Remix Icon is a set of open source neutral style system symbols elaborately crafted for designers and developers. All of the icons are free to use for both personal and commercial.
This is the best icon system that I know off. I have used it on many projects. I hope they continue making icons for it one day. I know that for now it has been discontinued. Not only are the icons great, but the site is super easy to navigate and export icons in various formats including some super compressed svg code.
