Warbreaker

A standalone Cosmere novel set on Nalthis, where magic runs on "Breath" — a spark of life force that can be traded, hoarded, or used to animate objects. Two princesses, a God King, and a mysterious swordsman collide in a city of vivid color and political machination.

Warbreaker is notable for being one of the best entry points into the Cosmere — it's a single, self-contained story with a satisfying conclusion. It also has important connections to the Stormlight Archive that reward readers later. Sanderson released the full text for free on his website.

Start here if you like: standalone fantasy, unique magic systems, strong character dynamics, or you want a free taste of Sanderson.