Powers & Abilities - Who used haki and who not?

We know prior to the timeskip we did not see hardening or CoA at all. CoO at least was hinted at (breath of all things, skypea, all the sensing/feeling

Opinions on this : r/OnePiece

Could Sugars power be undid by strong enough Haki? : r/OnePiece

One Piece: Is Advanced Conqueror's Haki the strongest power in the series?

Haki/Haoshoku Haki, One Piece Wiki

Powers & Abilities - Breath of All Things as Haki

I updated my Haki Skill Tree to show all the different ways in which you can master Haki! : r/OnePiece

Powers & Abilities - Is Luffy just using Basic Ryou + CoC? Is there a Level 3 Armament Haki/Internal Destruction CoA?

What are the different hakis in One Piece? - Quora

One Piece: What Exactly is Haki? Explained!

King's haki bullshit . No spoilers .. probably : r/OnePiece