It's a playful and endearing way to describe a group of people who may be small in number but make up for it with their energy, enthusiasm, and maybe even a bit of recklessness. It implies that while they might not be many, they are fiercely dedicated and passionate, making up for their lack of numbers with their spirit.
Think of it like a small, but mighty band of misfits who are ready to take on the world with their unique brand of crazy.