Making C4D's is fun, but time-consuming. I take most of mine from planet renders, since I'm so lazy. I found a set of about 18 amazing ones which work in any sig that I use over and over every time. It's pretty much like that for everyone. Go to Planet Renders, browse C4D's and fractals, and find some you like. You will find some you like, since there's so many. It does tak about a week to look at em all though.
Check back regularly too to see the new ones.
Alternatively, you can get Cinema 4D or Apophysis and start making em! Warning about this: You're wasting your life if you do it all the time, it sucks you in like mad.
Also, don't use other render/c4d sites. they suck ass, planet renders has all of theirs and 20 times more.