I've pictured a few I found in each material. (click on the image to bring you to the source)
I love the natural use of wood in these baby chick bookends.
The fabric idea for bookends is also great. The endless options of fabric you can use makes it so fun.
A little bit of metal in a room can be unexpected and fun. These metal robot would look amazing in a boys room. And you've got to love the little heart.
And clean, white ceramic...love.
I'm on the hunt for a pair of bookends for my kids room. I may have to venture to the second hand stores to see if I can find something with some unique character to make our own. Wish me luck!