This is a good question. However, the question makes the assumption that there is a paint that covers everything in 1 coat, which I don't believe is the case. My recommendation is Benjamin Moore's Aura. Now the fine print. Aura will cover very well because it dries to approximately twice the thickness of other paints. However, Aura says it will cover any color in never more than 2 coats, but there are exceptions to that as well, including some deep reds. The main thing is the color change. If the color you are using is within the same family of colors, you have a chance, we've also had pretty good success of grey covering over tan in 1 coat, but if you're making a major color change, don't expect any paint to cover perfectly in 1 coat.
Some other 1 coat coverage paints you could use would be Sherwin Williams Duration, and Behr Ultra Premium Plus.
Hope this helps!