If you are looking to purchase Mandarin books, you can look at:
Gloria’s bookstore
Yo Baby Shop
books.tw.com
Chinasprout.com
If you are looking for resources focused on character recognition, take a look at:
Sage books
Habbi habbi
LeLe books
We don’t advocate for TV time, but if your child watches TV and you would like for them to get some Mandarin in while they are watching, here are some good resources:
Little Fox Chinese – has free videos that you can also turn into audio downloads
Disney Plus – look in the language option to change shows to Mandarin audio
YouTube – please prescreen for inappropriate content
Netflix – A blogger has a list of her preferred Netflix children’s shows available in Mandarin: