What is gang a collective noun of?

The noun 'gang' is a standard collective noun for:

• a gang of bison
• a gang of buffalo
• a gang of convicts
• a gang of elk
• a gang of hoodlums
• a gang of hooligans
• a gang of prisoners
• a gang of slaves
• a gang of thieves
• a gang of turkeys
• a gang of weasels
• a gang of workmen