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:
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.
similarly, in Marvel Comics' The Eternals, it was revealed that many species were genetically tampered with by the alien Celestials.
Feline humanoids
This form has been popular. They are usually warrior-like as well:
Aliens that are created through technological means. This category also inculdes lifeforms that have been altered so that their existance depends on implants and other technologies.
C'tan (as above, woshipped and given corporial form by the Necrontyr, only 4 still exist and only two of those the Nightbringer and the Deceiver are awake, Mars (The Void Dragon) is actually one that was covered by space dust over trillions of years ago)(Warhammer 40,000)
The Chtorr , pink wormlike creatures from David Gerrold's War Against the Chtorr series. According to David, the Chtorr can also refer to the entire alien ecology.
the Doublers, two-in-one semi-humanoids of Stanislaw Lem's Eden
Drej , a race reponsible for the destruction of Earth; made out of pure energy, Titan A.E.
Trillions of Nicholas Fisk (small collective crystals)
Watchers in the dark (highly telepathic and thus invincible creatures who inhabit the rock Home of the Dark angles Space marines chapter) (Warhammer 40,000)
Yag-Kosha, from Robert E. Howard's Tower of the Elephant (humanoid elephant)
