Used, though rarely, as a noun meaning an unseen person, thing or intangible item; plural form 'invisibles' is attested.
Definitionen
A person or thing that cannot be seen, or an intangible item that is not physically perceptible. The story speaks of invisibles who guide humanity from the shadows.
An intangible asset, service, or source of income that does not involve the movement of physical goods (usually in the plural). Tourism and shipping are important invisibles in the nation's economy.