Porous Cave Variations

Proportion of air and block will be basically something like Swiss cheese that has a lot of air pocket.
Shape of air pockets could have various variations.

Also depending on surrounding biomes, main structures could be either stones, sand stones, terracotta and so on.

In vegetation rich area, some dirt pockets could form in air pocket and vegetations in it.

Near lake or coastral area, it could be soaked or submerged.

Also for deeper zone could have stone/magma block that forms structures and lava pools in pockets.

For higher height zone, some mountain structure could have porous structure or porous structure exposed on surface.

It could be very hard area to navigate but could provide a lot of visual and physical variation.

For reference, please image search with Porous Cave.