Void Hive is ridiculously OP on huge map.

[HyperKnight]

It saved me literal thousands of minerals allowing me to put them in research and armies, and even sell a couple thousands to buy alloys and repel corvette rush from nearby purifier.

[Anzaman]

It's one of my favourite ones, as it saves tons of minerals, construction ship time, and allows you to harvest resources you don't have yet have access to.

"Can exploit strategic resource deposits without technology with −75% output."

[mss73055]

Combine this with origin Imperial Fiefdom > Prospectorium.
Since you got so many minerals the hive can get a lot of research labs. And the advanced overlord adds 60% to that.