■■■アイコンをWindows8.1風に進化させませんか？ ■■■
Modern UI Icons
http://modernuiicons.com/
Windows 8のModern UIやWindows Phone風のアイコンがフリーで提供されている。
ライセンスもCC (Creative Commons) となっているため、商用利用や二次利用も可能となっている。
http://phpspot.net/php/webimager/admin3/data/fd916b264f9f50f9b4a42935fd31835e.png

Simple Icons
http://simpleicons.org/
http://phpspot.net/php/webimager/admin3/data/88f985c9ea667afa5cabd4b78879d389.png

icon8
http://icons8.com/download-huge-windows8-set/
http://icons8.com/download/icons/windows_8_icons_very_basic.png
http://icons8.com/download/icons/windows_8_icons_ecommerce.png
http://icons8.com/download/icons/windows_8_icons_transport.png
http://icons8.com/download/icons/windows_8_icons_buzz.png
http://icons8.com/download/icons/windows_8_icons_arrows.png
http://icons8.com/download/icons/windows_8_icons_media_controls.png
http://icons8.com/download/icons/windows_8_icons_file_types.png
http://icons8.com/download/icons/windows_8_icons_system.png
http://icons8.com/download/icons/windows_8_icons_social_networks.png
http://icons8.com/download/icons/windows_8_icons_photo_and_video.png
http://icons8.com/download/icons/windows_8_icons_text_formating.png
http://icons8.com/download/icons/windows_8_icons_overview_pages.png
http://icons8.com/download/icons/windows_8_icons_web_browsers.png