Ballet dancers. His work is swift and colorful. Very beautiful.
He worked with the impressionists (Monet, Renoir, Sisley, Morisot, Cassatt), Manet, Suzanne Valadon.
If you mean assistants helping him in his studio, he usually did not. Colleagues in the sense of other artists he knew, there was the whole gang of impressionist painters that he belonged to.
By making charming paintings. Also by teaching graphic work to Suzanne Valadon and encouraging Mary Cassatt. Those were interesting painters, working in Paris.
Edgar Degas, born Hilaire-Germain-Edgar De Gas 19 July 1834 - 27 September 1917
He painted about 1200 paintings. About one fourth of them ought to have been painted in the spring.
New Orleans
In order to paint it enlarged.
*Degas drew a ggrid over it to make it easier to copy.
There is no way of knowing how many artists there were in the world then or now.
Tens of thousands, anyway.