Sulochana
There have been three really famous Naga Princesses: Sulochana, Kumudvati and Uloopi
These three women are known for their beauty, devotion towards their respective husbands and their strong personalities.
Sulochana is mentioned to be a highly beloved and devoted wife of Meghnad. She was so devoted to him that instead of living without him in this world, she willingly followed him in death even when she knew even after Lanka would fall she would remain protected and honoured because the opponent was Shri Ram. She went to Shri Ram with permission of Ravana and Mandodari to beg for cut head of Meghnad which Laxman gave to Shri Ram as victory symbol.
Shri Ram tried his best to pursue her to not follow her husband in death, even offering to revive Meghnad back to life completely healthy but she preferred to respect her husband's martyrdom. Meghnad would have wanted to die like a warrior rather than coming back to life on enemy's mercy and she respected her husband very much. She took his head and cried and cried more and then she followed her husband in death. Her death gave immense pain to both parties and moved everyone to tears, such was her devotion towards her husband, she is considered one of the most chaste ladies ever born.
Kumudvati was daughter of Naga King of Sarayu river and her father was killed by Garuda. Ayodhya’s Kings were suppoters of Garudas as him being Vahana of Lord Vishnu. When Kusha (son of Shri Ram and Mata Sita) was sporting in Sarayu river with his wives (Champika and others), he lost a golden arm- bracelet gifted to him by his father. Servants told him Nagas took it and he brought out Garudastra to punish them. Naga King Kumud along with his sister Kumudvati came out and told him she took it by mistake when she was playing. He returned it and offered her hand in marriage to Kusha. He out of instant affection and to make Nagas his subordinate accepted her hand. More like it was a marital alliance after the weaker King surrendered and offered his sister for peace. Kusha got possession of most precious jewel (as said by Kalidas) called Kumudvati and Kumud , the Naga King got protection from Garuda by getting direct son of Lord Vishnu as his brother in law.
Despite the strategic nature of the marriage, Kusha and Kumudvati fell deeply in love. More so because she gave him his first son, Atithi which his first wife Champika was unable to give him. There was also an age gap between the couple because Kusha already had a married daughter who was Queen of Avanti (Kusha and Champika together had nine daughters).
When Kusha died, Kumudvati unable to live without him also followed him in death to reunite with her husband. In heaven they reunited and he shared half of throne of Indra and she shared Parijat with Indrani. Kalidas although doesn't explicitly writes it, he hints Kusha and Kumudvati as eternal lovers who couldn't stay apart and therefore reunited after death in heaven to stay together forever.
Both Naga Princesses of Ramayana era, Sulochana and Kumudvati were deeply and irrevocably in love with their respective husbands. They just couldn't process to live without them. By modern standards this seems like obsessive love and over dependence but in ancient era, such devotion was considered praiseworthy in a lady. Both women are hailed as chaste women but Sulochana is more popular than Kumudvati. Kumudvati is underrated because she didn't suffer any major tragedy in her marriage except death of her father, neither her co-wife Champika created problems for her. Kusha died in his old age after a war and she followed him in death.
Uloopi
Uloopi is a really strong and fascinating queen in Mahabharata. She was daughter of Naga King Kauravya. She was a lady with agency and made her own decisions. She fell in love with Arjuna when he was in exile and took him forcibly to her realm where he declined her offer of marriage but she reasoned with him and he accepted her hand. Later, they had a son named Iravan who died in Mahabharata war.
Uloopi is not a very major character in Mahabharata neither she is celebrated much but her strength, her courage to choose her own husband and her way of convincing Arjuna for love shows she was a strong personality.