cliparts para mapas mentais

http://commons.wikimedia.org/wiki/Crystal_Clear
http://www.dezinerfolio.com/2007/09/25/top-50-supercool-free-icon-sets/
http://www.supertrafego.com/icones_pacote.asp
http://www.iconarchive.com/category/application-icons.html  --muito bom

http://office.microsoft.com/pt-br/clipart/default.aspx -- Siteoficial de cliparts da Microsoft.