@Zincy
I only know of the Zerg, Flood, Aperoids and Necromorphs.
It’s a tough call on which is the most superior of those 4 because it really depends on the context and what you’d call a win condition.
Like, Necromorphs have easily the most powerful conversion method as it’s based on radiation and converts down to even the most inert deceased cell. If it comes down to a “zombification tug of war” over who gets control of a host, I think they win. Shoot, just dropping a Marker on any of the other’s controlled worlds would likely mean they can brainwash and convert enough of the opposing side to significantly tipped the odds in their favor. And if they somehow make it to Convergence and successfully make a Brother Moon? It doesn’t matter how you slice it, that’s GG right there. Their only real disadvantage is…they dumb. 99.9% of Necromorphs are just feral animals, with no real strategy beyond “Run like hell at whatever isn’t already one of them then slash the hell out of until it’s dead/another one of them.” Even the smarter ones don’t have a concept of technology, so whatever planet they’re on they’re stuck on until they make a Brother Moon. And most other spacefaring races aren’t opposed to nuking from orbit so…
Zerg holds a dubious distinction in the fact that their infestation can canonically be cured…and has been with surprising frequency. That pretty much means their infection method is pretty low on the totem poll. They definitely have one of the strongest armies out there, but if one of their leaders get converted then that’s an entire race under control. Even if psionic hive mind gets cut and the infested leader doesn’t just go “We with X now, play nice” then it’s canon that a leaderless zerg is so impotent that backwater hunters start hunting them for sport. If conversion wasn’t a factor I’d put them higher on the list, but their hierarchy gimps them against other zombie races.
It’s been so long since I played Star Fox that I forget the nitty gritty about the Aperoids. But from what I remember their main advantage over other zombie races is that they convert their victims into machine-hybrids. Other zombies need flesh to convert, but if the flesh is also metal that leaves them with a pretty big disadvantage. I’d almost say of these 4 the zerg would’ve been a hard counter for the Aperoids since zerg’s strength doesn’t lie in their conversion, but then I remembered zerg’s hive mind still gimps them if their leaders start getting converted.
In theory, the Flood should be the top dog of these 4, and I dare say of at least half the other races you mentioned. But their obscene, transcendental and metaphysical/multiversal feats are restricted to supplementary material and frankly doesn’t mesh well with their in-game depictions. So their main claim to victory is the fact that they can fairly quickly form a Gravemind to give their horde direction, and at that point you’re fighting a horde that can and will use your own technology against you. Doesn’t matter what, it’ll figure it out quick and now you’re fighting your own ships with tumors growing out of it.
So I’d say the ranking goes Zerg < Flood < Necromorph (assuming nuked from orbit before Convergence) < Aperoid < Necromorph (if Convergence is achieved).