To add more opportunities to get interesting minerals, gasses could be added in the form of 1 piece spherical gas giant entities. They would have spherical gravity because of the super round shape of gas giants and have a much bigger size than normal planets. These gasses could be refined at a lower ratio than ores, but the sheer volume makes it profitable. This could be extended to nebulas. An interesting way to add a twist is to arrange resources inside the gas giant by density, and that density yielding more resources.
Overall it is an interesting concept to ponder about.
Overall it is an interesting concept to ponder about.