Ulupi
Ulupi was a Naga Princess and she married Arjuna and with her free will. She had a son named Iravan who fought from his father's side and died in Mahabharata war. Ulupi is known to be a free willed and independent lady who married Arjuna because she fell in love with him.
Sulochana
Sulochana was also a Naga Princess and she was daughter of Sheshnaga. She was married to Indrajit (Meghnad) and when he died in the war, she went to Shri Ram to take back his cut head. He offered her to revive Meghnad as she wanted to self immolate herself but she refused and took the head and followed her husband in death.
Kumudvati
Kumudvati was second wife but Chief Queen of Kusha, King of Ayodhya. She had wished to marry him and they got married after he threatened to annihilate her entire race if he didn't find his arm bracelet which he lost when he was sporting in the waters of Sarayu with his first wife Champika and his other junior wives. Her brother Kumud offered the bracelet and her hand and he accepted her. Their eldest son Atithi became the new King after his death and she followed Kusha in his death as she couldn't live without him.
Nagas are divine creatures, descendants of Kadru and Kashyap. They worship lord of Nagas. Kumudvati was a staunch devotee of Lord Shiva and Kusha had built Nageshwarnath Temple near Sarayu river for her to pray.