I found the Stream Cheap model from DaveM at Thingiverse. But I wanted an LED to light up when I pressed the button and go out again after a certain time. That's why I ordered LEDs, buttons and the Arduino from Aliexpress to realise the project.
I also adapted the base to the Arduino from Aliexpress, as it is different from the original.
For the code please read the description of the original. DaveM has written this very well on his website.

Parts used:

Arduino: https://de.aliexpress.com/item/1005006100333649.html?spm=a2g0o.order_list.order_list_main.17.16945c5fz70xbO&gatewayAdapt=glo2deu

Switches: https://de.aliexpress.com/item/33006156813.html?spm=a2g0o.order_list.order_list_main.5.16945c5fz70xbO&gatewayAdapt=glo2deu

KeyCaps: https://de.aliexpress.com/item/1005005825113345.html?spm=a2g0o.order_list.order_list_main.35.16945c5fz70xbO&gatewayAdapt=glo2deu

LEDs: https://de.aliexpress.com/item/1005003337160679.html?spm=a2g0o.order_list.order_list_main.29.16945c5fz70xbO&gatewayAdapt=glo2deu