Rented a Polestar 2 multiple times from Hertz in the summer. It included both a home-charging cable and a charging fob.

The Hertz charging fob is quite expensive though, cheaper to signup to something like EnBW, which you can use for almost all charging stations [0].

Supercharger in Germany are almost all open to third-party cars as well, though not as cheap as EnBW.

[0]: https://www.enbw.com/elektromobilitaet/produkte/ladetarife