What cultures, if any (besides Ancient Egypt), believe(d) that the stars are other worlds/lands/islands?
Judaism, according to one interpretation in the Talmud of the verse in Judges 5:23:
"“Curse Meroz!” said the angel of the LORD. “Bitterly curse its inhabitants, Because they came not to the aid of the LORD, To the aid of the LORD among the warriors.”"
"...As it is written: “Curse bitterly its inhabitants” (Judges 5:23), in reference to all those sitting together with Meroz...And Ulla said: Barak ostracized Meroz with the blowing of four hundred shofarot due to his failure to come. As for the identification of Meroz, some say that he was a great man and that he was ostracized because he did not join in the war effort. And others say that the reference is to a star and not a human being, and that it did not aid the Jewish people in their battle, as it is stated: “The stars fought from heaven; in their courses they fought against Sisera,” (Judges 5:20). This star, which did not help the Jewish people, was cursed." (Tractate Mo'ed Katan, 16a)
The Babylonians, successors to the Sumerian civilization, held that the moving points of light in the sky which are the planets were the homes of their gods.
The holy books of Buddhism, on the other hand, appear to accept the plurality of worlds in countless numbers, complete with indigenous alien plant and animal lifeforms.
The ancient Vedda culture, which prospered on Ceylon prior to the Hindu invasion in the 6th century B.C., held that after death souls migrated to the Sun, Moon, and the stars before reaching Nirvana (the ultimate state of perfection). The beliefs of the Hindus are also closely associated with the idea of a plurality of worlds. The Indian philosophy, in fact, "explicitly assumes the existence of extraterrestrial intelligences."
To the Homeric Greeks, the Moon was an inhabited world separate from Earth, the dwelling place of protean gods and the spirits of departed humans.
Since other earthlike worlds might therefore exist, Xenophanes of Colophon - a contemporary of Pythagoras - populated the Moon with inhabitants, cities and mountains.602 Another Greek philosopher named Anaximenes evidently also believed in a multitude of celestial habitats, because he had the audacity to tell Alexander the Great that the Macedonian king had conquered "only one of many worlds."
The Roman poet and philosopher Lucretius firmly believed in a host of inhabited worlds. As he wrote in De Rerum Natura:
Why then you must confess that other worlds exist in other regions of the sky, and different tribes of men, kinds of wild beasts.... Nothing in nature is produced alone, nothing is born unique, or grows unique, alone. Each thing is always specimen -- of race or class, and many specimens belong to each.... That sky and Earth and Sun and all that comes to be are not unique but rather countless examples of a class."