Examples of collective nouns for people are:
A crowd, or a throng, or a mob of people is commonly used.
There are many more examples, depending on the nature of the group, two examples are: A Shrivel of Critics, and a tantrum of decorators!
Shoal is a collective noun. It is the collective noun for fish. A shoal of fish.The collective noun is a mint of candies
People is a community of more than one person, whereas peoples is a collective noun for more than one people.
No, the noun farm is not a collective noun.
There is no standard collective noun for a group of reflections. The noun 'reflection' is not a standard collective noun.
No, the noun lumber is not used as a collective noun. The collective noun for lumber is a stack of lumber.
No it is not a collective noun.
The collective noun is a series of explosions.
No, games is not a collective noun. The collective noun for games is 'a compendium of games'.
The collective noun is an anthology of poetry.
No, the noun land is not a collective noun. However, any noun can function is as a collective noun in a suitable context without being a designated collective noun.
The collective noun for 'wheat' is a sheaf of wheat.The collective noun for 'barley' is a crop of barley.
The collective noun is a drift of icebergs.