Not to be silly but...
Dried herb and flower leaves and petals
I use a product for clothes washing that is probably not sold there.
I do use the old fashioned cleaner here called Gumption I admit - for stubborn stains on tiles etc. It's like a thick paste but you only need a little and I would buy one a year only at most.
My son had a foul drain in his apartment and I poured baking soda down it and then hot water...left it a while and re-did it. No smell. It fizzed up and did a wonderful job.
Re the dried herbs etc. SO many commercial bathroom/room scents etc are made with throw away plastic and chemical compositions. If you have a really good assortment of dried leaves and flowers with a stick of cinnamon this often does a fine job as an air freshener. I love lavender too for this. Hanging a bunch up and it looks pretty.