You've probably never heard of an email id:
The best gift a parent can give their child is an email id.
You create an email id in your child's name, keep sending mails on a regular basis praising them on their small accomplishments they have made, let it be the 1st time they went to school or the time when they won a prize in drawing.
Capture these beautiful moments and mail it to them with images, write through your heart, write what ever you want to tell the adult them.
On their 18th birthday, give them the email id and password. :)
It's like a chest with their whole childhood in their - untouched, personal and very emotional!
Imagine the happiness in their face while going through those mails! Priceless!