Basement expansion - What usage possibilities?

It's actually not that expensive. We have set up a bar in our basement. Especially when my husband watches football with his friends, it is very relaxing. The installation of the toilet and shower was done during the house construction.

I have now also finished the basement. This way, I have set up a fitness room for us. It works out very well and here I can do my workouts in peace. Now, a wellness area will be added. That will come in [spring].