Perfection meaning stronger.
Kenbunshoku Haki
• Shanks.
• Silver Rayleigh.
It's hard to decide who mastered Kenbunshoku Haki to perfection but based from what I've seen, there's no such thing as mastering it perfectly because the moment you mastered/learn it, you already made it perfect. There are no more higher level of perfection to it. I'm saying Shanks and Rayleigh because they both seem like the haki master in the entire series and if there is perfection to Kenbunshoku Haki then I'm sure they're the one who achieved it.
Busoshoku Haki
• Shanks.
• Silver Rayleigh.
• Monkey D. Garp.
• Sakazuki.
• Zephyr [similar to Shiki, he is canon even though debated to being non-canon, there's more but I have no interest in spoiling more details to others who haven't watched the movie yet].
• Vergo.
The same as what I previously stated, but maybe there is perfection to it, we just haven't seen it yet. Shanks and Rayleigh are an obvious choice. From my point of view, Sakazuki and Garp seem to handle it pretty well and there's a chance they might be on the same level as Rayleigh and Shanks. But to me, currently, Zephyr seem to look as if he mastered it hence his epithet being "Black Arm". As for Vergo, he maybe haven't mastered it yet or maybe the second after Zephyr but the manga speaks for itself. He made it look like he's on steroid.
Haoshoku Haki
• Monkey D. Dragon.
• Shanks.
• Silver Rayleigh.
• Monkey D. Garp.
All four of them seem to be the likeliest to have mastered it. But Luffy also seem to mastered it during the Fishman Island arc but since he's still young, I won't put him on the list. Monkey D. Dragon is an obvious choice since he is the most wanted person therefore it's suited for the most wanted person to have this type of haki whilst Monkey D. Garp was said to have cornered Gol.D Roger and I'm sure he did not rely only on his strength.
All of this are the current one, I'm sure there are more people in the New World and Marines who mastered any type of haki to perfection.
