they

(the third-person plural) A group of people, animals, plants or objects previously mentioned.

“Dogs may bark if they want to be fed.”

(the third-person singular, sometimes proscribed) A single person, previously mentioned, especially if of unknown or non-binary gender, but typically not if previously named and identified as male or female.

“They requested a seat at Friday's performance but didn't say if they preferred the balcony or the floor.”

(indefinite pronoun, vague meaning) People; some people; people in general; someone, excluding the speaker.

“Ha, you believe the moon is real? That's just what they want you to think.”

There (especially as an expletive subject of be).