Nanites

Though they are only simple machines and very small, nanites can be used to achieve miraculous medical results in small amounts or astounding feats of engineering in mass quantities. Can be obtained by mining the following types of planets: Plasma Planet Storm Planet

Solid planetary resources are extracted from planet surfaces and feed the manufacturing chain for structures and advanced components. Output depends on the planet type you site the extractor on, so scouting the right planet matters more than the extractor itself.