Copper, Gold, Diamond, and Netherite Minecarts

Most players want improvements to Minecarts in general.

I believe there should be minecart variants, these variants will all vary in speed. And some of them should become structure loot, like horse armor. Only Iron and Copper will be craftable.

Their speeds should be as follows:
(Speed is Written in Blocks-per-second "BPS")

Iron Minecarts
-8 BPS (Remaining unchanged from current)

Copper Minecarts
-20 BPS (Un-oxidized)
-12 BPS (Exposed)
-8 BPS (Weathered)
-4 BPS (Oxidized)
The Copper Minecart will be either better or worse then the Iron Minecart, depending on its oxidation state. To justify this being the only other craftable cart

Gold Minecarts
-30 BPS
Can only be found as abandoned mineshaft loot rarely. Better odds in finding one in an abandoned mineshaft in a mesa biome

Diamond Minecarts
-40 PBS
Very rare piece of loot that can be found in 1 in 10 abandoned mineshafts

Netherite Minecart
-50 PBS
Found rarely in 1 in 10 Trail Ruins structures in one of their suspicious gravel blocks.

An Elytra has a max speed of around 33 BPS. Considering both rarity and infrastructure investment these faster carts have, I think its a fair trade off to make it a competitive and balanced choice.