There is no metal that truly does not corrode in air. Even "noble" metals like gold and platinum can corrode under certain conditions. However, some metals are highly resistant to corrosion and can be considered practically non-corrosive in typical environments:

* Gold (Au): Extremely resistant to corrosion, even in harsh environments.

* Platinum (Pt): Similar to gold, highly resistant to corrosion.

* Titanium (Ti): Forms a protective oxide layer that prevents further corrosion.

* Tantalum (Ta): Also forms a protective oxide layer and is highly resistant to corrosion.

* Iridium (Ir): Highly resistant to corrosion and often used in high-temperature applications.

* Niobium (Nb): Forms a protective oxide layer and is resistant to corrosion.

It's important to remember that the resistance to corrosion can vary depending on factors like temperature, humidity, presence of pollutants, and the specific composition of the air.

Therefore, while these metals are known for their high resistance to corrosion, it's not accurate to say they never corrode.