I was given Wonder Weeks which was useful in understanding phases, also used the Emma's diary app
I used wonder weeks with my first and will be using it again with my 2nd x
I also used the wonder weeks app, gives you an insight in to milestones baby should be hitting and actives to help, also helps show when sleep regressions are likely too 🙂
The Montessori Toddler is a great book and there is a Montessori Baby that I'm going to read this time around x
I found the app called Bounty great both during pregnancy and even now at 15 weeks postpartum. It gives you weekly updates about development.