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

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

Powers & Abilities - Who used haki and who not?

Why Crocodile didn't use haki against Luffy : r/OnePiece

One Piece: Haki And Its 12 Subtypes, Explained

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

Haki/Haoshoku Haki, One Piece Wiki

Completely unrelated but haki seems to give less/no resistance to awakened devil fruit abilities : r/OnePiece

One Piece: Strongest Abilities That Are Not Devil Fruit Or Haki

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

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

This is my understanding of conqerors and armament haki, hopefully it makes sense : r/OnePiece

Powers & Abilities - Z0lo was not a Haki user after cutting steel in Alabasta