This is an incomplete list of aliens that have appeared in various works of fiction featuring aliens.

Table of contents
1 Humanoid Aliens
2 Near-relatives of mankind
3 Feline humanoids
4 Insectoid Aliens
5 Centaurs
6 Reptilians and Amphibians
7 Aquatic species
8 Parasites and symbionts
9 Robotic and Mechanical aliens
10 Space-Living Creatures
11 Sentient Plants & Fungi
12 Ancient Races
13 More unusual forms
14 Shape-shifting aliens
15 Unintelligent creatures
16 Aliens From other Dimensions
17 Galactic communities
18 References

Humanoid Aliens

Most aliens are humanoid if not human-like, especially in TV series because actors are human. The Greys described in UFO folklore match this body type. Humanoids include:

Near-relatives of mankind

In these stories, these aliens are descended from the same ancestors as humanity:
  • Abh (Crest of the Stars)
  • Darrians of the Traveller RPG, known for their small, high-technology polity
  • Gethenians and other races of Ursula Le Guins Ekumen stories
  • Kromags of Sliders (descended from Cro-Magnons)
  • Nietzscheans (Andromeda)
  • Second through Last Men (Last and First Men)
  • Terra Novans (Star Trek)
  • Vilani of the Traveller RPG, known for their bureaucratic tendencies and empire building
  • Zhodani of the Traveller RPG, known for their psionic abilities
  • in Star Trek: The Next Generation, the episode "The Chase" revealed that all the humanoid races in the galaxy are the result of genetic tinkering by a single humanoid race in the distant past called The Preservers.

Feline humanoids

This form has been popular. They are usually warrior-like as well:

Insectoid Aliens


Reptilians and Amphibians

Aquatic species

Parasites and symbionts

Robotic and Mechanical aliens

Space-Living Creatures

Sentient Plants & Fungi

Ancient Races

Aliens that have either disappeared and left only ruins or developed to godlike- practically omnipotent entities.

More unusual forms

Shape-shifting aliens

Unintelligent creatures

Aliens From other Dimensions

Galactic communities