General collective nouns for people can be used for volunteers; a crew of volunteers, an army of volunteers, a couple of volunteers, a flight of volunteers, a corp of volunteers are all examples.

Foster Grandparents

General collective nouns for people can be used for volunteers; a crew of volunteers, an army of volunteers, a couple of volunteers, etc.

firefighters or a search and rescue team

A+.. Police officer in a bank

The possessive form for the plural noun volunteers is volunteers'.