Basta você ir no Google e digitar: Dragon png que irá aparecer várias render de dragão. Segue abaixo algumas:
http://i289.photobucket.com/albums/ll212/playou/medieval/Dragon.png
http://i494.photobucket.com/albums/rr306/tignstargfx1217/Renders/Fire-Dragon.png
http://images1.wikia.nocookie.net/__cb20100401223612/dragons/images/7/74/Battle_Dragon.png
Packs de Brushes:
Pack de Brushes do Mateus_RX
Sites de Brushes:
http://myphotoshopbrushes.com/
http://www.brusheezy.com/
http://www.dicasdodia.net/2007/11/100-melhores-brushes-para-photoshop-gratis.html