They would just look like spheres?

Not likely if they’re vacuum.

Yes likely if they're rigid, which is the whole point of vacuum balloons. The trick is coming up with a material that is strong enough to withstand the atmospheric overpressure trying to crush it, while also being sufficiently lightweight.

carbon nanotubes, the answer is always carbon nanotubes ;)

Like some foamy spheres. I couldn't understand if foamy spheres with a plastic film around them or just foamy spheres with self-contained holes.

Oh, and on the color of aerogels.

how about this. lets assume a sphere or egg shape is strongest and hardest to crush. create a bunch of ultralight tubes that are 12-18 inched long and crescent shaped. they are grouped in sets of 6 or more and are all connected at top and bottom by a small plastic ring. you slide them into a party balloon. and then give it air pressure, allowing you to spread them out with 60 degrees in between each crescent like an orange with all the slices. then you slowly let out the pressure so the rubber conforms against the 6 curves an makes a sphere at atmospheric pressure. then you pull vacuum, or simply place a bunch in a vacuum chamber and tie them off or glue the opening using something that wont react with latex

Don’t know why you were downvotes.

This technique has promise.

In short, you construct a shape made of inflatable cells which, when pressurized, contort in such a way that a vacuum is formed in the space within the collection of cells.

The problem, though, is that the additional air needed to make the cells stretch away from the center (and thus make a vacuum) is greater than than the air ‘missing’ from the vacuum part.

In any case, it’s been tried before:

“Vacuum/heat formed cushion with pyramidal, inflatable cells”:

https://www.freepatentsonline.com/5596781.html

The rubber membrane between the spars will not withstand the atmospheric forces.

14 pounds per square inch is a lot of force. A reference example, when planing a nuclear detonation(a grim task to be sure) the 5 pounds per square inch isoline covers the area where all non hardened structures(houses) are assumed destroyed.

https://nukemap.org/nukemap/