You will find random meteorites that can spawn in the Resource world
When you see the broadcast for meteorites, they can be found in the Resource world by typing /rw. From here, you will need to find the coordinates of where it spawned.
Keep in mind, that most meteorites will spawn a core, which is a barrel, and when opened, a strong Meteorite Guardian will spawn. This will earn you plenty of loot if succeeding in killing and escaping!
Not all meteorites will spawn a core... leaving it to just being a big ball of nothing.
You can sell most of the loot from the barrel and guardian in /shop at the Miscellaneous section. Which is unlocked once you reach Master rank.
Rank up to Master first, so you can sell the items from a Meteorite
This is a Netherite axe, which you can use, or sell for money
Chance to give various crate keys
A fancy emerald, that you should sell
A fancy Netherite ingot, that you should sell
A fancy Diamond, that you should sell
A fancy Elytra, which you can also sell for money