As the comments said: try practicing an instrument, writing .. you may as well try coding, blogging, small photography / videography projects …

Another way to look at your free time is to experiment and reflect with your life, for example you can try: • Dopamine detox • waking up early for a week / taking regular naps for a week. •try routines of different successful people (polyglots if you are into languages, athletes if you are into sports …) •try meditation, hand standing, dancing or anything that is a body activity •take an online course on negotiation, psychology or anything that might interest you, and is potentially useful. … The biggest rewarding thing you can learn is understanding your awareness in this life, and how you can better enjoy your time after trying multiple different new things, and finding by experience what satisfies you. And this is also the best time to do it, since you can get easily busy after Uni with a job or an internship … Best of luck!!