Copper, Tin, Iron, Lead. Gold is not considered an ore in Terraria.
Many video games with ores and mining follow a predictable pattern where “copper” ores are found the least followed by “tin” ores which in turn are less commonly found than “iron” ores which are finally less common than “lead.” The pattern’s logic states that the closer certain types of ore occur to each other, the lower their levels of rarity will be. While this trend has been generally true with video games in general for many years now, it can also make sense from a more scientific standpoint as well: deeper rocks and matter tend to have higher concentrations of metals because they’ve had thousands or millions of years to be built up by volcanic activity and natural decay.
Copper ore can be found as low as the first level of the game all the way to the height of almost any player’s world. Tin ore can be found in most worlds at a similar depth as copper, but it becomes less frequent deeper down (like with most video games). Iron is usually only found below depths of 25-50ft and lead can be found within 100ft or so – although certain ores of lead can be found at much greater depths, some being so high they may even be more common than iron ore. Gold usually occurs in the game as one of the final mining stages before reaching Demon Altars and only rarely will it not be present within these last few layers of rock.