For the light switches , as well as the ones for the fuel pumps and pitot heat I decided to make a wooden bar and mount it below the yoke.
They are basic 2 positon switches from Amazon, nothing fancy.

I also added a momentary button and wanted to use that one for the XBarometer plugin using an Arduino Leonardo. Unfortunately that part only worked while testing it alone. When I had both the SimVim Mega and the Leonardo connected X-Plane decided to crash after loading the plane/scenery. So for now I leave the Leonardo disconnected. I might try to switch the Mega to connect via a LAN cable later on and give it another try.
Maybe there is a way to call the PlugIn via a button, I have to look into that.

To hook it up to the Mega I use an input extension board which is compatible with the CD74HC4067 one recommended on the SimVim website. This is the first actual non-testing part I added with SimVim and I love it because it is so super easy. One of these days I have to either become a Patreon for some time or just donate some money directly.

Angela helped me mount it and this is the final result: