I have memories from before starting school of a few Dutch-language books around the house. There were Tintin comic books in Dutch translation, but I could never do much with those beyond looking at the pictures. (I should ask my parents whether we still have them, as I might be just at the right stage for them now!) The simple vocabulary and picture books were more useful.
My sharpest memory is of a Dutch translation of Richard Scarry's The Best Word Book Ever, with its household and community scenes inhabited by cute little human-like animals and labelled in great detail. I had the original English copy as well, so I could compare if I wanted to, but it wasn’t really necessary. I would spend lots of time poring over the pictures, and some of the vocabulary just stuck.
I remember visiting the family farm in the Netherlands when I was eight years old and “playing house” with the neighbour’s daughter, who was the same age. Despite the language barrier, we were able to build an open floor plan out of bales of hay, and we did lots of gesturing to make ourselves understood. I wanted a broom to sweep up the bits of hay, and I was proud as punch when I suddenly remembered the word “bezem” from the Richard Scarry book, and she understood me right away. Using a word successfully in context was an encouraging thrill. If Scarry’s books were translated into Dutch, I have no doubt they were translated into several other languages as well, so these may be worth hunting down in children’s bookstores on your travels.