The internet is as replete with exotic buildings of exemplary design as the real world is filled with concrete contortions and architectural afterthoughts.
Here's a list of eight ultra-low-energy passive buildings from around the world. It says they are passive houses, but they may not all be certified, or even meet the standard. They are all at least based on PH principles.
One of them is particularly interesting as it's a dome. As far as I know there are no certified passive house domes, which is a bit surprising. I'd love to find out more about the halo dome in China, but searching for it on Google mostly arrived at a vape pipe. I wonder if they left any cookies.
Domes are very energy efficient shapes, with a lower surface area to volume than any other. The only way to get a better form factor is to start turning it into a sphere and bringing it out of the ground. You sometimes see water tanks of that design. Even then, you may be better off with a hemisphere since the ground tends to be warmer than the air in the winter, so less heat will be conducted than into the air. On the other hand, heat is often more convected than conducted to air, so the conduction to the ground may be higher. Also, there would be less radiation and less convection from the parts of a protruding sphere pointing downwards. I probably need to investigate this more.
Looking at the geometry of form factors, a single storey dome of any size has the same form factor as a completely square two storey standalone building. If the dome has many storeys inside, it will have a better form factor than anything. The only problem is building without straight lines and right angles. A trivial problem when you're sketching ideas on paper, but a huge problem when you're procuring building parts and giving instructions to builders.
