IconShock - Over 2 million free icons in 400+ icon sets over 30 styles
Nucleo - Commercial vector icons and accompanying apps to manage and customize them.
Iconoir - A diverse and open-source library with 900+ icons
Icon Shelf - Icon Shelf is a free and open-source SVG icon manager for web developers.
Streamline icons - The world’s largest icon pack library - 100k icons and illustrations.
Glacier Icons - A free icon set for your Mac