What's considered the best kind of dental crown (material) to get for the tooth that needs it is the last molar on bottom?

Bruxir Zirconia . Solid zirconia crowns are the strongest crowns available. They are great crowns especially for those who tend to grind or clench their teeth. E-max crowns are also excellent crowns. Both of them are tooth colored crowns. High noble gold crowns are very strong but are not tooth colored. Most people will do great with an e-max crown.
Full porcelain crown. But make sure you ask for zorcania, bruxer crown.
No one best. Yellow gold crown cannot break, requires least tooth reduction, but is unesthetic which is not an issue for most people if not seen. Other choices are numerous kinds of ceramic or ceramic on metal crowns. Every material has pros and cons. Trust your own dentist to discuss options and make recommendations.
Zirc, emax or gold. The kindest material long term for 2nd molars is high noble gold; great combination of strength, durability, and flexes very similar to tooth enamel, (the most biocompatible). Monolithic (solid) zirconia and lithium disilicate (emax cad) have become great alternatives since they have great strength and are tooth colored; they can sometimes be too hard, and flex differently than tooth, though...