What words can I replace the pronoun they with?

The personal pronoun 'they' can takes the place of a plural noun or pronoun for people or things; and two or more nouns or pronouns for people or things, as the subject of a sentence or a clause.

Examples:

They are the customers that have waited the longest.

They themselves told me about it.

They are the books that I ordered.

They are Jack and Jill Smith.

They are oranges and Apples.