Some mirror!verse fabulosity:
Vengeance by
lalazee - PG13, ~560 words; “I would destroy worlds for you.”
Et tu, Spock? by TGuess - All Audiences (G/PG), ~3000 words; Jim is Caesar, with a beautiful twist.
Nor Thorns Infest The Ground by
jane_potter - R, long PWP; "This is the first time Spock has ever said he wants to be with Jim. This is possibly the first time Jim has ever touched somebody gently. So Spock's consent is conditional and Jim has to deal with the Vulcan's sick little touch kink, so what? Their happiness, it seems, is to be mutual if it is to be at all."
Bend Me, Break Me, All I Want Is You by
verizonhorizon - Adult, 4700 word PWP, "By manipulating Kirk’s fantasies, Spock telepathically cock-blocks his captain until he gets what he wants." What he wants is fantabulous top!Kirk, apparently. Author has a few other similar fics.