Collective nouns uniquely describe a group of the same kind and often reflect their characteristics, such as a flutter of butterflies, bury of rabbits, and a cast of falcons. For painters, the term 'group' is commonly used.
The collective nouns for various groups of animals and people can often be quite picturesque and allude to some characteristic quality or behavior associated with the group.
A flutter of butterflies captures the light and airy manner of these insects, while a bury of rabbits suggests their underground homes. Similarly, a cast of falcons refers to the way falconers used to 'cast' their birds off their arms to hunt.
Finally, for humans in creative professions like artists, we might use a group of painters; however, collective nouns for people are less standardized and can be subject to preference and context.