Right now the only thing I have that is not a bulb, switch, or dimmer is my garage door. It's using the custom Zooz Garage Door driver and I want to save the closed state of the door in a scene. It's connected via a Zooz Zen16 multirelay and I can't include the state of the relay because the relay just turns on for a second to short a connection to open/close the door and then turn off. The relay being off doesn't tell me if the door is open or closed.
You can't. 
...at least not directly. But you can use some Scenes app features to get what you want in the end. The only catch is that it won't be reflected in the scene state, i.e., the "(Set)" or "(Not Set)" description you can see at the end of the scene name, indicating whether the devices are in the state specified for the scene being activated or not (it will only look for devices that are really part of the scene). The feature I'm thinking of is the "Select button to push upon scene activation" option you see when creating the scene in the Scene app. You can create a virtual button, add it to this option when making (or editing) the scene, and then set up another automation that calls the desired command on your ZEN16 when that virtual button is pushed. Button Controller or Rule Machine would be easy choices for that.
If, by chance, the ZEN16 driver also lets you do this by way of a push() command for a specific button number (I'm not familiar with this driver), then you can actually bypass my virtual button idea and just use this in the Scene app directly. But that's probably just wishful thinking on my part...
There are probably other ways to get there, too, but this is something that sounds like it would work for you.
I ended up just making a rule with the scene activating as a trigger. I was just hoping to be able to add it to the scene itself so I could use the metering that scenes provide. I just added in a small delay into the rule.
It's a scene that basically turns everything off when we leave the house. Chances are, we'll remember to close the garage door, but I wanted to add it for peace of mind. In the future, I'll probably be getting some locks too so those would also need to go into my rule instead of the scene.
I use tilt sensors (SmartThings Multipurpose sensors) mounted on my garage doors. Unfortunately, those sensors are no longer available, but there may be other options.
The sensors use the X,Y,Z axis readings to determine whether the doors are vertical (closed) or horizontal (open).
You can also mount a contact sensor on the edge of the door and the magnet on the door frame. If the door is closed, the sensor will close. If the door is open even a few inches, the contact will open.
I have a rule that is set up to turn the house lights on if the garage doors or outside doors are open between 10 pm and 5 am the next morning; we are usually in bed during that time. I do not have a rule for the day time as we can leave the garage doors up or other doors open for hours at a time during the day. I have occasionally left a door open at night, so I want to be alerted if I make that mistake. That would also serve as an intruder alarm if someone forced a door open in the middle of the night.
