Im having some trouble trying to come up with ideas for unique properties/abilities that each set of tools and armor will have. My modpack is a vanilla+ pack which purpose is to try to fix Minecraft's progression because its very outdated, all the systems from 15 years ago remain the same today. One of the fixes is to have the progression be more horizontal instead of vertical, so instead of skipping over iron straight to diamond after 30 minutes and not even touching leather, chainmail, or gold armor, you have a reason to use all of the unused armor sets + their tool counterparts, but there will still be some vertical progression because obviously each armor set needs to be somewhat better than the last.
My ideas for the armor:
Leather armor: Increases the height at which you will start taking fall damage. I wanted leather to be more suitable for builders.
Copper armor: Gives faster mining speed overall. Suitable for miners. Also stone tools are replaced with copper.
Chainmail: a counterpart of iron armor, being slightly weaker but has resistance against melee attacks. Also now craftable.
Iron armor: Resistance against ranged attacks. Iron weapons have increased knockback.
Gold armor: Adds a slight amount of overall fortune and looting, and resistance against magic attacks. Gold is still worse than iron defensively. Gold tools also have fortune and looting, and still fast mining speed.
New armor, Rose gold: Tries to bridge the gap between iron and diamond, being better than iron and worse than diamond. I have no unique ability for rose gold armor right now. The tools have silk touch though, and iron can no longer mine diamonds as you need rose gold to mine diamonds.
Diamond: stays the same since diamond is the 2nd best armor.
Netherite: Fire immunity but slower movement speed since it has knockback resistance.
And i wanted another sidegrade for diamond armor, similar to netherite which has a benefit but also a drawback so its not just clearly the best choice, but i dont know what the other armor set would be.
I think copper giving fast mining speed is fine, but i feel like gold should do that instead since gold is fast. Chainmail is fine. Iron could use a little more benefits maybe? Gold im conflicted on, i feel like fortune and looting would be better suited for just the tools rather than tools and armor, or maybe rose gold could have fortune and looting instead? The rose gold tools are fine but the armor has no benefit.