May 2015 Update:

ECOMMERCE LINE ICONS
ECOMMERCE LINE ICONS

231 Micons – Free Icons Set
231 Micons - Free Icons Set

These outlined icons are well crafted and playful. The consistent style is visible in all 231 icons and are a must-have for your collection.
30 Responsive Icons By ICONS8
30 Responsive Icons By ICONS8

Flat Icon set
Flat Icon set

Vector Gesture Icons
Vector Gesture Icons

A set of more than 50 free gesture icons designer for multi-purpose devices.
Free Transport Icon Set
Free Transport Icon Set

48 Bubble Icons
48 Bubble Icons

Game UI icon set
Game UI icon set

Smashicons: 300 Free Icons
Smashicons: 300 Free Icons

60 Free Vector Line Icons
60 Free Vector Line Icons

Happycons: 40 Happy and Unique Icons
Happycons: 40 Happy and Unique Icons

Happycons is a pack of 40 essential icons designed in a happy and unique manner by Darius Dan. All icons are built on a 180px grid and are available in multiple formats.
Random Stuff Free Iconset
Random Stuff Free Iconset

Sport Related Icons Pack
Sport Related Icons Pack

Free Space Icons
Free Space Icons

Free flat icons for landing page
Free flat icons for landing page

Free Science Icons
Free Science Icons

Blunicons – 60 Essentials Icons
Blunicons – 60 Essentials Icons

Here is a remarkable set of 60 essential icons designed in an unique manner. All icons are free to use in your various projects and are available in multiple formats.
Free Icons for Illustrator and Sketch App
Free Icons for Illustrator and Sketch App

Ego – 100 Vector Icons
Ego – 100 Vector Icons

Check out this original set of 100 free icons designed with a radical angular style guaranteed to make your designs stand apart.
38 Arrow Icons
38 Arrow Icons

70 Free Simple Icons
70 Free Simple Icons

New York Buildings Icons Set
New York Buildings Icons Set

File Types Icons
File Types Icons

20 file types flat color icons: image, video, zip, doc, xls, csv, html, jpg, txt, envelope, charts and more.
Popular Landmark Icons
Popular Landmark Icons

50 Free Construction Icons
50 Free Construction Icons

9 Coffee Icons
9 Coffee Icons

Foody Icons
Foody Icons

45 Fresh User Interface Icons
45 Fresh User Interface Icons

21 Flat iOs icon Set
21 Flat iOs icon Set

Free Art Thin Line Icons
Free Art Thin Line Icons

25x Editable Icons
25x Editable Icons

40 Good Idea Icons
40 Good Idea Icons

Kölsch Icons
Kölsch Icons

80 Flatilicious Icons
80 Flatilicious Icons

Free icons Vkontakte Concept
Free icons Vkontakte Concept