In Srimad Bhagavatam, in the 7th chapter of the Dasama Skandhas, Yudishthira's Rajasuya Yajna is described. It is compared twice to a Rajasuya performed by Varuna.
SB 10.74.13-15 — The utensils used in the sacrifice were made of gold, just as in the ancient Rājasūya performed by Lord Varuṇa. Indra, Brahmā, Śiva and many other planetary rulers; the Siddhas and Gandharvas with their entourage; the Vidyādharas; great serpents; sages; Yakṣas; Rākṣasas; celestial birds; Kinnaras; Cāraṇas; and earthly kings — all were invited, and indeed they all came from every direction to the Rājasūya sacrifice of King Yudhiṣṭhira, the son of Pāṇḍu. They were not in the least astonished to see the opulence of the sacrifice, since it was quite appropriate for a devotee of Lord Kṛṣṇa.
SB 10.74.16 — The priests, as powerful as gods, performed the Rājasūya sacrifice for King Yudhiṣṭhira in accordance with the Vedic injunctions, just as the demigods had previously performed it for Varuṇa.
So what is the story of Varuna's Rajasuya Yajna?