Inappropriate products

Avoid food products which could lead to health problems later, such as obesity, dental caries, etc. Many children’s foods are so high in sugars and fats. See for instance the Australian Consumers’ Association Choice Magazine articles:

Choice Magazine: Foods that make kids fatter faster
Choice Magazine: Reviews and tests of kids' foods

Why design a package of unhealthy food that attracts children to consume it if we know they will suffer health problems later? Would you want your own children to suffer diet-related ill health? Wouldn't it be better to spend your time designing an excellent package for a food product that is nutritious as well?

Consider  safety of toys and their age appropriateness and educational play value. See for instance

Choice Magazine: Toy safety tips
Business Pundit: 10 bizarrely inappropriate children's products

Stay  away from products which “sexualize” children. There are products sold in pharmacies such as mascara, lipsticks, tattoos, exfoliants, waxing strips, etc for young girls . Some web articles on this:

The Week: Anti-aging makeup for 8 year old girls

Good Men Project: 11 insanely sexually children's products
Cracked: 8 weirdly sexual products for kids