Any is followed by Plural countable nouns or uncountable nouns. This is in questions and negatives but not positive statements. For example: Do you have ANY siblings or money? I don’t have ANY siblings or money.

It doesn't always need a plural. For example: Do you have any interest in history? Do you have any time to discuss this? Do you have any sense of humour? Has there been any trouble here? Why can't we have any peace in the world? That dog will eat any flavour of pizza.

As Andrew Wright says, "any" is followed by either a plural noun or an "uncountable" (non-count) noun. All of the examples that Richard London gave are non-count nouns, which is why they are not plural. Some nouns can be either countable or uncountable, depending on the context. For example: "Do you have any INTEREST in history?" (uncountable) "Do you and your brother have any INTERESTS in common?" (countable, plural)