About filling the drawers: my sister made me an advent calendar of small felt pouches several years ago, and we've been filling it for each other since. The pouches are approximately 4 cm too. The first time I received it she had put a piece of paper with a recipe into each pouch, and also a small surprise like candy, a sticker and once I got a small bag of saffron for the recipe of that day. This year was my turn to get the calendar again and so far I've received craft supplies: clear stamps, ribbons etc. Two years ago I got a metal puzzle from couple of pouches. I've filled it for her with glass beads, candy, tiny cookie cutters, paper craft supplies. For a kid you could also use small toys, like plastic animals.
My partner's page is half done now. I like it a lot so far, hope the rest will turn out as good too. I'm going to a 100 year birthday party today (2 people, both turning 50), and if I don't have a hangover tomorrow I'll probably finish the page.