I've seen several groups "identified" with them from the Mandeans to the Hermeticist but as mentioned above I'm distrustful of Wikipedia and the Internet at large.
I quote here from Abdulla Yusuf Ali commentary for the verse 62 in Sura 2 of Holy Quran, this is where one occurrence of sabians is in the Quran
Latest researches have revealed a small remnant of a religious community numbering about 2,000 souls in Lower Iraq, near Basra . In Arabic they are called Subbi (plural Subba). They are also called Sabians and Nasoraeans, or Mandaeans, or Christians of St. John. They claim to be Gnostics, or Knowers of the Great Life. They dress in white, and believe in frequent immersions in water. Their Book Ginza is in a dialect of Aramaic. They have theories of Darkness and Light as in Zoroastrianism, They use the name Yardan (Jordan) for any river. They live in peace and harmony among their Muslim neighbours. They resemble the Sabi'un mentioned in the Qur'an, but are not probably identical with them. The pseudo-Sabians of Harran , who attracted the attention of Khalifah Ma'munal Rashid in 830 A.C. by their long hair and peculiar dress probably adopted the name as it was mentioned in the Qur'an, in order to claim the privileges of the People of the Book. They were Syrian Star-worshippers with Hellenistic tendencies, like the Jews contemporary with Jesus. There was another people called the Sabaens, who played an important part in the history of early early Arabia , and are known through their inscriptions in an alphabet allied to the Phoenician and Babylonian. They had a flourishing kingdom in the Yemen tract in South Arabia about 800-700 B.C., though their origin may have been in North Arabia . They worshipped the planets and stars (Moon, Sun, Venus). Probably the Queen of Sheba is connected with them. They succumbed to Abyssinia about 350 AC. and to Persia about 579 A.C. Their capital was near San'a . They had beautiful stone buildings, in which the pointed arch is noticeable.