For extraterrestrial beings:
* Extraterrestrials: This is the most direct and scientific term.
* Space aliens: A common, informal term.
* E.T.s: A shortened, informal term.
* UFO occupants: If you're focusing on their potential presence in unidentified flying objects.
* Visitors from another world: A poetic and suggestive term.
For foreigners or non-native people:
* Foreigners: A general term for people from other countries.
* Immigrants: People who have moved to a new country to live permanently.
* Expats: People who live and work in a foreign country.
* Outsiders: This term can be used to describe anyone who is not part of a particular group.
For something strange or unfamiliar:
* Unknowns: This word emphasizes the lack of knowledge about something.
* Strangers: This term suggests someone who is not familiar or known.
* The unknown: A more poetic term for something that is mysterious or unclear.
Ultimately, the best word to use depends on the specific context and the meaning you want to convey.