In terms of "largest"... I had been playing a game on the
Sins Plus mod as the TEC. I had Relativistic Factories, and quite a few factories on an Industrial planet (Halves build time), as well as the tech that lowers build time of ships. The economy had been maxed and I had a great trade route. The tech for fleet supply was at or near max, I can't remember. For fun, I started
swarming scout frigates, and turning on the autoattack as they were built. I cannot remember how many I had near the end, but it would destroy my frame rate if I zoomed in.