All you have to do to make your own is go on google images and write in 'outline clipart'. there's loads to choose from, just save the image to your computer. When you have collected all the images you want just open word (or whatever you have) and randomly place the pictures on the page. Then print out, your done!
to play say to your child 'i spy a tree' or whatever, and once they found it they colour it in. And when you play next time, just re-arrange the pictures around before you print the sheets out