Earth's Mightiest Heroes. Originally founded by Iron Man, Thor, Hulk, Ant-Man and the Wasp, the Avengers have been the premiere super-hero team of the Marvel Universe ever since. A full list of members unrelated to the X-Men would be too numerous, but presently:
Steve Rogers has joined forces with SHIELD, leading a team of Avengers during the Incursions to hunt down the Illuminati. Captain Marvel and War Machine are members of this squad.
The Mighty Avengers organization sided with Rogers during this feud. Spider-Man is a member of this squad.
Other Avengers refused to hunt the Illuminati and forged a separate unit to investigate the Incursions. Sunspot leads this squad, which also includes Cannonball and Spider-Woman.
Rogue, Quicksilver and Scarlet Witch are involved with the separate Avengers Unity Division.