Animals: First to domesticate turkeys, llamas, guinea pigs, and honeybees for food.
First to cultivate Cotton and Rubber.
Medical Contributions: Quinine for the treatment of Malaria (that alone saved God knows how many lives worldwide) and figured out long before the Old World that citrus and other foods high in Vitamin C prevent scurvy.
The Mayans were the first culture to use zero in mathematics.
The League of Iroquois introduced concepts of federated democracy.
Other Native American contributions are detailed here:
Native American contributions - Wikipedia, the free encyclopedia