In Germany they sell those travel sizes in some larger supermarkets and most dm, rossmann and budni stores. In good mostly easy to re-use containers even. They have everything from mouthwash and toothpaste over lotions and soap and even sunscreen. It's wonderful for travelling with carry on as the liquid rules are still enforced and an industry has built around it.
I especially like that I can get stuff hotels might not provide in travel kit size like sunscreen a good mouthwash and a good hand lotion.
I sometimes refill cause the tiny bottles are comparatively pricey and throwing the used ones away seems wasteful but I enjoy that I can even stock up on the road