All are related to Gautam Bhudha and Kautilya also mention many self governing clans in which these exist.
Sakiyas of Kapilavastu: A republican clan with the capital at Kapilavattu, was a vassal of King Prasenjit of Kosala It was a great center of Buddhism
Koliyas, a republican clan had 2 chief settlements in Ramagama and Devadaha. Buddha was related to the Koliyans through his mother and wife. After the demise of the Buddha, the Koliyans obtained a share of his relics and erected a stupa over it.
Mallas had 2 confederacies; one at Kusinara and the other at Pava Kusinara was famous as it was the site of Buddha’s Mahaparinirvana. Malla Roja initially opposed Buddhism, later accepted him after he heard the Buddha’s discourses.
Bulis of Allakappa, Moriyas of Pipphalivana and Kalamas of Kesaputta. They were followers of the Buddha.