Given the vague lack of criteria, I chose the leaders I've played who are strongest, more or less taking into account civ abilities as well, but leaving out Cyrus since I never actually used his leader ability--but I'd add that I think Persia is nevertheless a powerhouse.This guy is so overpowered it is insane. Virtually free boosted Industrial District + synergy bonuses with Commercial District = absolutely insane forvictory condition. I tried winning a science victory with Barbarossa, but my district game was so on point I accidentally won a culture victory first.(This was before they nerfed Industrial District overlap, but I'm pretty certain he's still insanely OP.)I underestimated her before I played as her, but her trade route bonus makes her veritably swimming in wealth from quite early in the game, while the Iteru ability can be an enormous boon if you start with enough river access (the game I played as her, it would have been difficult for me tobuild districts and wonders next to rivers).Just getting three districts for half cost is pretty potent, and the adjacency bonuses synergize really well with that.Honorable mention forCulture bombing and yet more potent trade routes.Honorable mention forDon't underestimate the bonus she receives to tourism; my fastest culture victory to date was as Catherine, thanks to triple tourism from wonders.Now a couple I was rather disappointed with:While he can indeed grow some incredibly large cities, he otherwise doesn't actually have a lot going for him. Maybe my start location was poor, but to date the only game of Civ6 I lost was as Kongo.Those adjacency bonuses can be(I've had over +6 bonuses) and the carnival is interesting, but overall he seems more middle-of-the-pack.Extra builder charges, using builders to rush wonders, bonus culture and tourism from the Great Wall, and bonuses to Eurekas/Inspirations makes him look like a great contender for culture victory on paper...but in practice he extremely underperforms compared to his wonder-building competitors, Cleopatra and Catherine de Medici. Plus he looks like a toad.