Box set of series suggestions – 3 year old boy

Happy Sunday lovelies ! Hoping for some suggestions!

I am looking for an age appropriate box set or series of books I can grab my nephew for Christmas. My sis and I have discussed that I won’t be getting him Harry Potter until he’s 7 so I have a few more years.

He reads a lot, my sister reads to him all the time too. There is also a one year old girl, and a new baby coming too so anything that may also work.

He loves Harry Potter and dinosaurs. Loves working outside with dad and his hands. The guy also has a fantastic imagination!!

Thanks in advance everyone !