There is no Free Art Definition, but the Free Art License is in the spirit of this definition.
The Free RPG Community (or FRPGC) is a volunteer organisation dedicated to free content advocacy for roleplaying games. The Free RPG Community believes that all material for roleplaying games should be shared freely without monopolistic restrictions.
Cf. the Free Software Definition.
Internet Engineering Task Force
The Internet Engineering Task Force (IETF), which is the body governing the drafting and evolution of Internet protocols - without which the Internet, an unified interconnection of physically disparate networks, couldn't even exist -, has rules concerning the rights that are granted on its published documents. Although a subtle restriction on derivative works makes some of these documents not completely free, it is a good example of how Free Content's essential freedoms can be fruitfully applied to promote scientific and technical progress.
Cf. the Libre Communities site for associated definitions, including Libre Knowledge.
Cf. the Open Knowledge Definition.
Cf. the Open Source Definition, but note the philosophical differences to the Free Software movement; also note that the term is, in spite of its definition, somewhat diluted, especially in contexts other than software.