Most collective nouns imply a degree of commonality between the individuals forming it.
A herd of cows feed together, return to the farm for milking together and even , occasionally, act together to protect each other from a perceived threat.
A crowd of people, even if they have not come together for a specific purpose, are aware of each other and their actions can be influenced by other members. The awareness of a flash mob by members of the crowd in a shopping centre will spread as people notice that their neighbours are looking at something they have not yet spotted themselves.
A collection of AIs will have some degree of commonality in this sense and at least some of their communication will use formal networking, probably the internet in most cases. An appropriate collective noun, therefore, might be cloud. This would give sentences like "A cloud of AIs will monitor the High Street watching for muggers and pickpockets."
A good thing about using cloud in this way would be that the AIs could be of different types. In the High Street example there could be drone-implemented AIs flying around, mounted camera AIs capturing higher-quality images and at least one server-based AI coordinating the activity, receiving information received by the others and matching faces with a database, possibly hosted on a remote, AI controlled server. All these AIs, however would be part of the same cloud.