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

Limitations of Armament-Haki : r/OnePiece

Opinions on this : r/OnePiece

One Piece: Forget Haki, these 5 powers will astonish you with their abilities

What are the different hakis in One Piece? - Quora

One Piece: All Haki Types and Its Subforms (Explained)

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

One Piece: All Haki Types and Its Subforms (Explained)

1039 Spoilers) You're Wrong About Haki - Understanding How Oda Writes Powers and Abilities : r/OnePiece

Why was Haki not used during the Marineford War, as every vice-admiral and up are said to possess it? - Quora

Did Ace use Haki in One Piece?

What is the next level of Conqueror Haki? - Quora

All Conqueror Haki in One Piece, Ranked