Alien: Covenant (2017) follows Walter One and his crew who investigate possible human voices on a nearby planet but soon two crew members get infected.
Alien: Resurrection (1997) follows Ellen Ripley as she is revived as a powerful human/alien hybrid clone as she must again battle the deadly aliens.
Aliens (1986) follows the story of Ellen Ripley after the destruction of the Nostromo when she wakes up after a stasis into a new generation.
Alien 3 (1992) follows Ripley when she survive Sulaco and wakes with inmates in another colony to fight a loose alien without any weapon on board.
Alien (1979) is directed by Ridley Scott and is about a crew who must survive an alien which has been released on their ship. The fight for survival begins.