The following online stores offer vegan baby and toddler shoes.
Clamfeet: Offers adorable baby shoes and matching shoes for mothers. They have an eco-canvas exterior, organic cotton lining, and rubberized grip sole. They are washable. https://clamfeet.com/
Happy Little Soles: This UK company offers a vegan section of shoes for boys and girls. They ship to the US. https://www.happylittlesoles.co.uk/
Ten Little Shoes: Offers vegan shoes for kids. https://tenlittle.com/
Tom’s: Sells vegan shoes for children worldwide. Search under the word vegan. https://www.toms.com/us/kids/shoes
Vegan Chic: Offers a few options for children including The Kid’s Ramos by Keep. https://www.veganchic.com/kids/vegan+shoes/search.aspx