What is the collective nouns for organisers?

There isn't a widely accepted or commonly used collective noun specifically for "organisers." Here are some options you could use, depending on the context:

General terms:

* Group of organisers

* Team of organisers

* Committee of organisers

* Staff of organisers (if they are employed)

More specific terms:

* Conclave of organisers (implies a formal gathering)

* League of organisers (implies a group united by a common purpose)

* Force of organisers (implies a powerful and influential group)

You could also use more descriptive phrases like:

* A gathering of passionate organisers

* A network of dedicated organisers

* A corps of efficient organisers

The best choice depends on the specific situation and the tone you want to convey.