[Suicide Junkie]

Planetary Indices, using the equations. Pop growth rates, production and build rate, even some atmosphere modification, all based on race settings among other things.

High organics-value planets would convert CO2 into oxygen, high rads (of the volcanic variety) planets would emit lots of H2 and methane, and more.

And a separate reproduction rate and death rate index.
You could have a heavy metal value for the planets, which could reduce reproduction rate in regular races (toxic), but be required for self-reproduction in the case of mechanoids.
You could have planets where a small colony will die off from natural events unless you can grow it to a stable size, or keep feeding replacements to it as the people die.

You could have a rapidly-reproducing race that uses up all the methane, say, in an atmosphere and then dies off when the methane runs out.
They would come in giant pop transports, turn the atmosphere into population, and then leave to find another world to consume.