Basically, any Bluetooth keyboard works with the tablet.
Since I work with several Bluetooth devices, I bought the Multi-Device Keyboard K480 from Logitech.
With it, up to 3 devices can be paired at the same time with a simple rotary control.
The keyboard is also available at Digitec under the following link:
Logitech Multi-Device Keyboard K480 (Bluetooth, CH, Wireless)