Everyone is gangsta until the Culture shows up.

And the second place is i think Honorverse missile deluges.

I was consistently downvoted on the 40k reddit discussions when i pointed out that Warhammer navies would be probably splattered by forces from most other established settings even if simply because they are really slow and half of their weapons (everything that isn't lances really) would be completely unusable in combat against them.

Idk if i mentioned it here, but there is long and quite interesting fanfic about Culture spreading to 40k galaxy, and interestingly enough they only thing Culture had a problem with were the warp influence, prophecy powers of Tzeentch sorcerers, and maybe their own undecisiveness about orks. Tyranids for example were just erased in passing.