Hello need advice from parents

Hi i am a student trying to earn some money through amazon kdp for my college fees.I have

decided to make activity books and colouring books .There are lots of options on amason for that but i am confused.I am here to ask for advice if your child is of 3-6 age which type of book like cartoon,flowers or any religious book would you buy for you kids so that they can also learn with colouring .