List of fictional alien species: I

Name	Source	Type
Iberons	Imperium Galactica II: Alliances
Ibs	Robert J. Sawyer's Starplex
Ice Warriors	Doctor Who	humanoid
Iconians	Galactic Civilizations II: Dread Lords
Iconians	Star Trek
Ifshnit	Star Frontiers	Humanoid, meter-tall
Ikrini	Battlelords of the 23rd Century
Ilanics	Farscape	Humanoid
Ilwrath	Star Control	Spider-like
Imsaeis	Master of Orion
Imskians	DC Comics' Legion of Super-Heroes
Ing	Metroid Prime 2:Echoes	Beings native to a dark mirror dimension. Some can change into forms relating to solid, liquid, and gasseous states. They have the ability to possess and corrupt both living and dead creatures. Main enemy to Luminoth.
Insects	The History of the Galaxy series
Interions	Farscape	Humanoid
Invid/Inbit	Robotech: The New Generation and their counterparts from Genesis Climber Mospeada	crab-like
Irkens	Invader Zim	Green humanoids (usually small) with an appetite for destruction
Isanians	Perry Rhodan
Ishtarians	Poul Anderson's Fire Time
Ithanites	Star Trek
Ithkul	Master of Orion III
Ixtl	The Voyage of the Space Beagle by A. E. van Vogt