You can find many clip arts with slightest modifications yet with different subject matters either, thus there is a continuing process of preparing, producing and using of these school clip arts by a lot of people. With everything else changing so fast, I believe it is valuable to retain some things essentially as they have "always" been. If your little one is fascinated by Disney characters such as Donald Duck, Mickey Mouse or Tinker Bell, you can selectively choose to print coloring-pages on this particular theme. Cartoon characters tend to constantly fall in and out of fashion. If the current trend is that of Ben 10 or the Incredible, you can easily generate hundreds of printable coloring sheet based only on these cartoon characters. The minuscule effort it takes to compile an on demand coloring book is worth the smile on your child's lips.
You might have heard of alphabet color pages that are used to teach preschool kids and toddlers. They are taught alphabets and relate them with their surroundings. Similarly the Biblical coloring pages are there too for getting direct print from your computer and show them to your children. The world of web has been really delightful in these matters. You can find ready made color pages in hundreds of styles and colors that also contain Biblical themes, stories like Noah's Ark, the Whale, miracles of Jesus, about the birth of baby Jesus, Mother Mary, Easter, Gift of Magi and alike. The use of these coloring sheets is perfect to teach preschool children the values and morals of Christianity, the true meaning of religion and how to become pious.