Actually some people misunderstand sometime, they think they can use anything that is under creative commons license. But there any many versions of creative commons license and they are totally different from each other. That means anything under any versions of creative common license can or can’t be used on TF items. Example : Any item under this license http://creativecommons.org/licenses/by/3.0/ can be used for TF items but anything under this version of Creative Commons license can’t be use http://creativecommons.org/licenses/by-nc/3.0/ To say straightly anything that is under any type of license that grant permission to redistribute and grant permission to use commercially then yes you can use that. So always keep in mind if anything says that the author give you permission to redistribute it and give you permission to use it commercially then you are free to use that on any item that you want to sell on Envato market places.