Products that promote entertainment and creativity are always my favorite. I love the Scribbles: A Really Giant Drawing and Coloring Book. In this book, there are coloring and drawing prompts to inspire your child and help them have a unique coloring experience. This book would work well for ages 3+, as long as there is an adult or older sibling that can read the prompts.
I love these examples from my niece from her book. It has provided hours of entertainment for her.
There are also other products similar to Scribbles:
There are even postcards that you could have your child make and then send off on your travels back to grandparents
Do you have a coloring or drawing book you just love?