Very true. Devaki's cousin Kamsa was the ruler of Vrishni kingdom. In the Puranas he is described as rakshasa (demon). He overthrew his father Ugrasena (not biological father) and became king of Mathura. Once he head a heavenly voice that said Devaki's 8th son will kill him.
He wanted to kill Devaki but Vasudeva saved her saying all their babies will be handed over to him.
The cowherd chief Nanda Baba too is worshiped. His capital Nandagaon is a religious place. It is near Barsana in Braj, Uttar Pradesh. He resided here with followers and other cowherds. His residence is called as Nanda Bhawan. First three years of Lord Krishna's childhood were spent here. It houses a famous temple too called Mahavan.
There is one thing missing in this discussion. Krishna was exchanged with Yosada's daughter Yoganidra or Yogamaya. Both the babies were born on the same day. Yosada was not aware of the exchange and believed she had given birth to a son. Well, back at the Kamsa's end, he found Yogamaya as the 8th child of Devaki and tried killing him. She assumed her real form of Devi. She flew to the sky. Thereafter she retired in Vindhya hills, which is now called as Vindhyavasini Devi.
Yogamaya was the incarnation of Durga. She vanished while Kamsa tried to kill her, but she predicted that Kamsa will be killed at the hands of Krishna. She is worshiped by Hindus at Yogmaya Temple, which is a Hindu temple shakti peetha. It is in Mehrauli, New Delhi, near to Qutb minar.