Essentials for 2 under 2!

🌻🌺Trinkster🌺🌻 • Mamma to my little man 10/02/18 and little girl 11/29/19

I'm currently a mom of a 6 month old and 7 weeks pregnant. What are some things that will be necessary for having 2 under 2? I'd like to start saving some money now for anything we will need!