Best independent student jobs you've done

Hey guys, once again I am asking for your collective knowledge! I am currently pursuing a quite demanding Master's degree and I am thinking about jobs that allow me to be independent (e.g. work during night if I have courses during the day) and still earn some money. Do you have any suggestions from previous experiences? It's totally fine if it doensn't earn much, it would even be okay if your suggestion doens't earn anything in the short-term and builds up over time :D. Let me know what you got!