I've started wiring up new gauges, using the single (1813g) and double (2813g) from https://www.auberins.com.
These are high fidelity digital displays.
I have small 9 pin toggle switches where I can flip between two different probs on the same display, though that doesn't change the alarm, or other, settings. For example, one display can show both pre and post radiator temperatures with a flick of the switch.
So far, I'm going to measure the following.
Coolant Temp, - pre and post radiator.
Oil Temp - pre and post radiator
Oil Pressure
Transmission Fluid Temp-pre and post radiator.
Transmission Fluid pressure

What else would you measure? It can be pressure, temperature, such as cylinder head, air intact, or engine bay? Pressure, voltage (though I already have that displayed in another gauge).
In your dream World, what would you like to have displayed?

 

Cool, are you wiring up your own transducers for these gauges? I think you have all of the "important" bases covered, anything else is going to be niche or just for fun. You might be interested in manifold vacuum/engine load or air intake temperature- I've thought several times about putting a resistive liquid level sensor in my coolant tank so I can have some warning when it gets low because to me that's way easier than actually fixing the tiny leak...

 

I just purchased the pressure cables.
I'm adding a low coolant detector, but it will require TIG welding, so that will be in a few months. I have the Carrs4x4 reservoir, but adding a monitor means drilling out an access hole, then welding a large panel on. I have the parts already, but will get to that install in the Summer.
Air intake and Engine bay temps can be on the same gauge, I don't think I need to set an alarm for those.
I have it so that if a gauge alarms, a buzzer is trigger, and a separate indicator light is triggered as well.

 

I am using the auber gauges for oil pressure, oil temperature, water temperature and voltage. The silly cup holders under the hvac controls were removed and I had a simple bracket fabbed to mount the gauges. Hope that helps to get the wheels turning!

 

It was pictures, such as yours, that lead me to using the Aubrer gauges. I'm putting 4 in that exact area, and at least one on the A pillar (the 52mm round ones) and the double gauges will also fit under the Coin and Ashtray areas.