IF: artificial...

Something that sells well on stock image sites are realistic looking vectors.  The artificial reality is quite good for the buyers as, unlike the real thing, it allows for scaling (without losing image quality) and they're easily edited.  So far we've created realistic baseball caps, desserts (like one of our most popular pieces, a realistic chocolate covered strawberry),

and yesterday i finally got around to creating an artificial corkboard:

What's nice about this is that I can use this piece, and add more paper or different types of paper or even add words to add a variety of different stock image choices for perspective buyers.
You can find these and many more on stock image sites such as shutterstock, istockphoto, dreamstime, and fotolia.

And it's nice to do these every once in a while because they're completely different from the children's book illustration stuff I usually do.