A benevolent race that, gave rise to Norse mythology on Earth and inspired accounts of the Roswell Greys. The Asgard can no longer reproduce and therefore perpetuate themselves by transferring their minds into new clone bodies as necessary. Extremely advanced technologically, the threat of their intervention shields many planets in the Milky Way from Goa'uld attack, including Earth.
Ori are Ascended beings who use their advanced knowledge of the universe to force lesser beings to worship them. In essence, they used to be Ancients, however they split into separate groups due to different views of life. The Ori are religious while the Ancients prefer science. The Ori sway lesser-developed planets into worshiping them by promising Ascension through an invented and empty religion called "Origin". This religion states that they created humanity and as such are to be worshiped by their creations. It also promises its followers that, on death, they will Ascend. However, Origin was designed to channel energy from the human worshipers to the Ori. As such, the Ori never help anyone else Ascend because then they would have to share the power that they sap from their worshipers. Their ultimate goal is to completely destroy the Ascended Ancients, who they know as "the Others". All of their efforts, including their technology, are for the purpose of garnering worshipers.
The Wraith, are the dominant species in the Pegasus Galaxy. They are biologically immortal hive-based humanoids who feed on the "life-force" of humans, causing them to "lose years" in a way similar to aging. The Wraith drove the Ancients out of Pegasus 10,000 years ago; they now maintain the human worlds of the Pegasus Galaxy as sources of food.