YES! You can freely use these icons to print on tshirts.
YES! You can use them as a logo, social network photo, 404 HTML page, whatever!
Please send me pictures or screenshots of it :-)
BUT, to include the whole pack as an asset in an application/website, that your users can use, you must ask for my authorization
KAMELEON - 120 Free Icons That Change Color
STREAMLINE- 100 Free iOS8 Vector Icons
MINICONS - 210 Free Minimal vector Icons
FONTASTIC- Generate Your Icon Fonts in Seconds!
Check also: Vectorian: Vintage Vector Ornaments