Joshua A. Davies

Designer First — Simple Icon Set

Splashnology — 50 New & Fresh Icon Sets

Splashnology — 50 Fresh Freebies from Dribbble

Design Your Way — A Roundup of Stylish Free Icon Sets

Land of Web — Weekly Fresh Web Design Freebies

Web Design Ally — 13 Free Flat Outline Icon Sets for Web UI Design

100 Sets of Minimalist & Free Outline Icons (PSD & Vector)