Conrad, a German electronics seller, has a number of different advent calenders in their choice of products, among them e.g. electronics: https://www.conrad.de

Conrad, a German electronics seller, has a number of different advent calenders in their choice of products, among them e.g. electronics: https://www.conrad.de/de/search.html?search=adventskalender%20kalender&searchBarInput=adventskalender%20kalender https://www.conrad.de/de/search.html?search=adventskalender%... They offered sets with Raspis, Arduinos, breadboards and components in the past and over the course of December, people could slowly progress with building their first (usually relatively simply) circuits and projects by receiving additional pieces and schematics every day.