auto.png
Author: Babasse (Sebastien Durel)
License: Creative Commons Attribution
http://findicons.com/icon/19310/performance_systeme_os?id=330918

business.png
Author: Visual Pharm
License: Creative Commons
https://www.iconfinder.com/icons/17220/business_cash_change_coins_funding_money_payment_icon#size=256

comedy.png
Author: Flameia Design (Julia Nikolaeva)
License: Freeware Non-commercial
http://findicons.com/icon/37962/laughter?id=412319#

education.png
Author: PixelPirate
License: Free for non-commercial use.
http://www.iconarchive.com/show/futurama-icons-by-pixelpirate/Professor-Farnsworth-icon.html

fashion.png
Author: Andrea Aste
License: Free for personal desktop use only.
http://www.iconarchive.com/show/new-york-icons-by-andrea-aste/a-day-icon.html

film.png
Author: Babasse
License: CC Attribution-Noncommercial-No Derivate 3.0
http://www.iconarchive.com/show/old-school-icons-by-babasse/bobines-video-icon.html

health-and-fitness.png
Author: Babasse (Sebastien Durel)
License: Creative Commons Attribution
http://findicons.com/icon/19285/anti_virus_old_school?id=389831

politics-and-history.png
Author: Iconica Custom Icons (Maria)
License: Freeware Non-commercial
http://findicons.com/icon/21806/url_history?id=21914#

lifestyle-and-leisure.png
Author: IcoJoy
License: Freeware
http://www.iconarchive.com/show/enjoyment-icons-by-icojoy/leisure-icon.html

music.png
Author: Treetog ArtWork
License: Free for personal desktop use only.
http://www.iconarchive.com/show/junior-icons-by-treetog/folder-blue-music-icon.html

science-and-space.png
Author: schollidesign
License: GNU/GPL
http://findicons.com/icon/93166/applications_science?id=274510

sports.png
Author: Icons-Land
License: Freeware Non-commercial
http://findicons.com/icon/48265/boxing_gloves?id=277992

travel.png
Author: Icons-Land
License: Freeware Non-commercial
http://findicons.com/icon/28543/airport?id=381908

video-games.png
Author: Mart (Marco Martin)
License: GNU/GPL
http://findicons.com/icon/49613/package_games?id=375972