pliant moon
The number of dupes tends to be a big hinderance on game performance later on. Rather than taking on extra dupes, it would be cool to be able to upgrade dupes to require +1000 calories/cycle and +100g/s of oxygen but get a flat +10 bonus to some/all attributes (prior art in neural vacillator if that helps). This could stack multiple times and be a reasonable alternative to laggy pathfinding later on. Note my suggestion could also apply to critters, but that might be more challenging to implement (critters which requires more to feed but drop more meat)
torn nimbus
jolly thunder