I'll start with a few books but I'm sure others can suggest foods, drinks and various bits and pieces.

Books -

Bathing Etiquette A History Of The Baths Caring For Your Zentu Bathing With Your Zentu

The Shengui Guo Tea House is opening soon, so my suggestions will wait until I see what we're already getting. I can totally see all of these books as selling there in the gift shop portion.

Books at the Bathhouse are super expensive as far as books go and it's impossible to read them to all your pets at those prices and bathhouse points are too rare to score that many books for yourself. So as far as releasing all of these there, ... meh.

I'm not sure why a tea house would sell books which are about the baths.

Does anyone have any ideas for new bathhouse shop items? The wearables aren't exactly versatile but a long and short bathrobe which colour match the towels could be useful.