We've discovered super-earths orbiting around 11.8% of stars. These planets are 1-3x the size of the Earth (easier to detect), although we can only speculate to their elemental composition. We still don't know how many Earth-sized planets are out there, but they appear common [0].

A highly advanced technological society could even fuse hydrogen to synthesize the lighter elements in our periodic table. Imagine the sheer volume of hydrogen readily available in a single nebula (many stars worth).

If a civilization could climb enormous gravity wells, Jupiter itself has 318 times the mass of the Earth, ready for space mining.

https://www.nasa.gov/topics/universe/features/exo20101028.ht...