For books specifically I found an amazing “franchise”. It’s called Bücher Brocki (https://buecher-brocky.ch/). It’s in Aarau, Basel, Bern, Luzern (this one what kind of underwhelming) and Zürich.
They have thousands of used books, sorted by themes. It’s mostly german books but there always is a decent sized alley for english and french books.
The price are insanely low and people constantly bring them new books to renew their stocks so you can find real gems.