some of the artists on Deviant Art make amazing C4D renders. here's a link to some: http://www.deviantart.com/#order=9&q=C4D+renders
here's the first one i used, they're pretty good ^_^ http://xbry89x.deviantart.com/art/C4D-Concept-Pack-61223270
I don't like using ones off of dA because some people require that you credit them or link back to them -- I like to just save the ones I like to my computer and use them as I please. I get mine at Planetrenders.
I am Pretty sure Planetrenders is free, so it doesn't matter mush anyhow. I got renders from there but i am not sure if i had to cheat... Not that it matters anymore, i just make my own, as i render better than most people that i've seen...