I happen to enjoy both minimalistic and graphic intensive wallpapers and these two website that I'm about to share will really give you some sort of design delight.
If you wanna go minimalistic, try SimpleDesktops.com
On a side note: SimpleDesktops.com has an application at the Mac App Store that will allow you to manage wallpapers. I have not purchased the application since it's $3.99~170 Pesos. It's nice to have but if you have time to choose and change your wallpaper then you really don't need it.
|Screenshot of the Simple Desktops App from the Mac App Store|
The other website where I get more graphic intensive wallpapers (and some simple ones) is Kuvva.com.
They have so many wallpapers by different artists. It could be a painting, vector art, drawing or a photo. On their about page they mentioned that they "..want to turn dead space into creative space" which is really true. Check the website out to see what I'm talking about.
On a side note: Though I'm feeling the minimalistic vibe right now, I have the Kuvva Wallpapers app installed on my MBP. This app automatically changes your wallpaper when the clock hits midnight. You should go to the website, create an account and choose which wallpapers you would like to appear on your desktop screen otherwise the app will choose randomly. Check it out on the Mac App Store. It's for free.
|Screenshot of Kuvva Wallpapers on the Mac App Store|