Indefinite determiners are categorized into six groups:

Distributive indefinite determiners refers to unidentified members of a group. These include 'each' and 'every.'

'Each' comes before a singular noun to refer to all members of a group individually. For example:

'Every' also refers to all members of a group, but unlike 'each' it refers to the group as a whole rather than individually. Take a look at the examples:

Existential determiners refer to an unknown or unspecified set and include some and any. Each of them is used in specific contexts.

In its most common usage, 'some' refers to an unspecified quantify. In this usage, it can only modify ucountable and plural countable nouns and is used in affirmative contexts. For example:

Additionally, 'some' can refer to a portion of a larger whole. In this case, 'some' refers to not all of something, but just a part of it. In this sense, it can modify all nouns and be used in both affirmative and non-affirmative contexts.Here's an example:

A less common usage of 'some' modifies an indefinite singular countable noun to refer to an unknown person or thing. In this case, it is typically interchangeable with the indefinite article 'a/an.' For example:

'Any' commonly refers to an unspecified and unknown entity. In this case, it is only used in non-affirmative contexts, that is, in questions and negative sentences. For example:

Another common usage of 'any' is called the free choice, where it indicates that no specific quality or restriction is considered for the noun that follows it. In this case, it can be used in both affirmative and non-affirmative contexts. Look at the examples:

'Either' and 'neither' are called disjunctive determiners. They both refer to sets of two people or things, but are used in different contexts.

'Either' is like 'any' in that it has a non-affirmative and a free choice usage. But it is different in that it specifically refers to two entities. Look at the examples:

'Neither' is the counterpart of 'either' in affirmative sentences. It is itself a negative marker and expresses absence or lack of the noun it modifies. Accordingly, the verb of the sentence must remain affirmative. For example:

'No' is commonly used as a determiner before a noun to show a complete lack or absence of that entity. It can be used with singular and plural as well as uncountable nouns. Look at the examples:

The alternative-additive determiner 'another' is formed by adding the indefinite article 'an' to the adjective 'other.' As a result, it typically comes before singular nouns. As the title suggests, 'another' has an alternative and an additive sense. In other words, it can introduce a second, different option as well as implying one more item of the same kind. Take a look at the examples:

Quantifiers like 'many,' 'much,' 'few,' 'little,' etc. refer to an unspecified quantity or amount. Unlike most other determiners, these have comparative and superlative forms: 'more,' 'most,' 'less,' least.' While 'many' and 'few' modify plural countable nouns, 'much' and 'little' are exclusive to uncountable nouns. Look at the examples: