Quetzalcoatl

Quetzalcoatl (KETz-uLL-koAT-L) is the Mesoamerican god of wind and knowledge. AD&D's Deities & Demigods describes him as "the mightiest god of his mythos," but like many things from that era of D&D the truth is a little less cut-and-dry. In Aztec mythos, Huitzilopochtli (WITs-ee-low-pocht-lee) is the god of War and Sun, who is arguably much more powerful. In Maztica he appears as Qotal. The Couatl are also based on him.

Quetzalcoatl gets used as the patron deity for Lizardmen in pretty much every fantasy setting that has them, mostly because it's the only Aztec god that most GMs can pronounce. If you're running a setting utilizing Aztec or Mayan culture, he's an auto-include in your pantheon. It is worthy of note that Quetzalcoatl is largely opposed to human sacrifice in most of the myths involving him. Since Aztec's casual practice of human sacrifice is anathema to modern morality and is what caused the Spanish (with the help of other natives the Aztecs kept around to produce sacrifices) to destroy the Aztecs in the first place, this makes him the only choice for a remotely benevolent Aztec deity.