In a recent game playing as a custom faction the Elerians(Ancient + Exterminators, basically evil Altarians) I came across 3 chimeric biomass artifacts and I managed to make 2 super planets. Both of these arent fully optimized due to some short term decisions made earlier in the game.
The first is my homeworld Elaria. Highlights: Quantum Power Plant, Singularity Power Plant, Antimatter Power Plant, Strategic command for +50% ship construction, Orbital Defense Platform + Helios ore to level up Startport and Enginnering Center, Temple of Despair. Also produces a ton of food so somehow its both an industrial and farming planet.
TFor the second, I took a level 5 active core planet, settled it with the mercenary that gives a +20% raw production to the colony it founds, and then suck most of my chimeric biomass charges into it. This probably wasnt the optimal decision, but it turned out fine.
Highlights: Pragmatic Precursor Fabrication Plant, Idol of Chains(+50% ship construction),Shrine of Agol(+3 to all), Quantum Power Plant, Manufacturing Capital, Planetary Defense Dome, Starport, Resupply Center, Death Furnaces.