I recently participated in a secret book exchange. Not only did you have to get your giftee a book, but you also had to create or buy a bookmark. My kids were able to participate too and had other kids to exchange with. It was a lot of fun. We created our bookmarks, drawing 1 each for our 3 giftees (a total of 9).
We chose the Nightmare Before Christmas for 1, a Batman reading set/activity book for 1, and an adult Coloring book/with reading books for the last. So we ran with those themes/ideas for the bookmarks. I am in awe of my 5 year old’s drawings and my 2 year old covered both herself and the paper in marker. My kids’ bookmarks were amazing and creative. I was able to play more with ink and sakura pens on special paper (Mi Tientes).
For finishing we laminated our bookmarks with contact paper which believe it or not is relatively easy. Though I wouldn’t recommend letting kids help with that part.