Well, since cannibals usually means people, the collective noun group will work just fine. But, for the most part, cannibals in a group are a thing of the past so you may be speaking historically. At times in history that it was believed that groups of people practiced cannibalism as a group, the reference was usually used for remote tribes that were separated from English speakers by distance or status and therefore inexact at best. In other words, in a historical context, a collective noun for cannibals would be prejudicial and probably inaccurate.
The type of cannibals that may be found in groups today would be people who were stranded by accident or natural disaster who are starving; or groups of people who have come together to share certain psychopathic personality traits. In the case of modern groups of cannibals, choose a collective noun that suits the group you are referring to.
A hearty meal
The collective noun is a company of firemen (firefighters).
The standard collective noun is a pool of typists.
Collective nouns for waterfowl when flying (including ducks, geese, coots, etc) are a skein, string, or team.A group of waterfowl in the water can be called a bunch, paddling, or raft. A group of any waterfowl can be called a plump.
The collective nouns for 'vipers' are:a nest of vipersa generation of vipersa den of vipers
There is no standard collective noun for a group of names, however, collective nouns are an informal part of language. Any noun that suits the context of the situation can function as a collective noun; for example, a list of names.
The collective name for a group of sailors are called a crew
A group of goldfinches is called A CHARM
A group of spies is called a "Nest"
A group of spies is called a "Nest"
That is the collective name for a group of Wolves, a "pack".
The collective name for a group of rhinos is "a crash". http://encyclopedia.thefreedictionary.com/Rhinocerous
The collective name for the petals of a flower is the corolla.
There is no collective name for a group of platypuses. Platypuses are solitary animals and do not live or move in groups.
The collective name is a bed of clams.
The collective name for badger is 'sett'
The name is a collacine
A group of maidens is called maidens. There is no word to signify a group. A maiden is a girl or young woman who is unmarried.