What should I fill an Advent calendar with for a 7-year-old boy?

Thanks for responding to my demand, with I must confess, with “multifacely interested” I cannot start much. These are almost all children of age, but most of them have a horse. At least the children I teach.

Shame, Dinos are out. Well, that might come back sometime. I’m collecting them today, with over 40. Meanwhile, I have a Dino socket.

But what does he really like to do? And how big are the individual “doors” from the Advent calendar?
For example, if he likes to draw or paint…a few pens, brushes, individual colors (for example tubes acrylic paint), chalks etc. It often doesn’t cost much, and in the end you have a lot of things together.
In general, there is a lot that stimulates creativity.

Or if he collects something like someone has already addressed the Pokemon cards. There are also other collection areas, such as semi-precious stones (which are often already cheap), old coins, for example my niece (also 7) collects, according to my grandmother, all where a unicorn is on it – if necessary. the bubble also has such a “password”, e.g. matchbox cars, etc.

Does he want to knock a geode on his own? They are now also available to buy and cost between 2 and 5 euros. Or maybe a kit for crystal breeding, which is just distributed to some “doors”. The things of cosmos are always quite good for my students.

Does he like to play detective? I’ve just got one in the class that’s very interested in…Lupe, fingerprint powder, brush etc. That’s pretty good.

There is actually quite a lot… even relatively favorable. But there’s too much to know someone you don’t know and about whom you don’t know anything except “is versatile”.