Molecular clouds

A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H2). This is in contrast to other areas of the interstellar medium that contain predominantly ionized gas.

Molecular hydrogen is of great  value as fuel base and therefore scooper operations, refineries and  gravo collector bases are very common in or around Molecular clouds.

Molecule Cloud harvest controversy
While these clouds stretch ovr many light years and "depleting" them would take thousands of years. There are small groups chief among them the Gal Drifts who see the harvesting ov Molecule clouds as a crime against nature.

However the Space salvage law lets anyone to claim or harvest anything found in space. (see Space Salvage Laws for limitations)