An indefinite pronoun is a pronoun that refers to non-specific beings, objects, or places. Indefinite Pronouns can also function as other parts of speech too, depending on context.
Most indefinite pronouns are either singular or plural. However, some of them can be singular in one context and plural in another. For examples:

Singular Indefinite Pronouns List;
Another, anybody, anyone, anything, each, either, enough, everybody, everyone, everything, little, much, neither, nobody, no one, nothing, one, other, somebody, someone, something

Plural Indefinite Pronouns List;
Both, few, fewer, many, others, several