According to Christian theology all Pagan deities are demons. So, when we speak on the names of the demons, we have to consider that there were incorporated to Christian demonology Jewish demons, Pagan deities, folkloric supernatural beings, and sometimes imaginary names given by people interrogated under torture during the witch trials, by mentally ill persons (energumens) that were considered demon possessed, imaginative priests, etc.
In this way we have Jewish names like Asmodai (Book of Tobit), Azazel (Leviticus 16:8-10), Belial (Deuteronomy 13:13, Book of Judges 19:22, Books of Samuel, part 1, 1:16, 2:12 10:27 and 25:17, and part 2 16:7 and 22:5, Books of Kings part 1, 21:10-13, Books of Chronicles, part 1, 13:7); Semitic deities like Adramelech, Baal (see Baal (demon)), Moloch, Astaroth (derived from Astarte); Greek, Roman and Egyptian names like Bifrons (See Bifrons (demon)), Lamia, Phoenix (see Phenex); and so on. All biblical references were taken from the Vulgate.
Sebastian Michaelis in his classification of demons (see Michaelis' classification of demons) gives more names.
Goblins, Drudes, Familiars and other folkloric creatures became part of Christian demonology.
In this way, there is no agreement on who is who for many names that originally were only one have been separated in several entities, and others have been "created" by people, like Sonnilon, Olivier, Raum, etc. Besides, many demons have several spellings of their names, not all of them with a valid fundament.
However it is, it seems that all societies have the need to give names to those real or imaginary entities that represent "supernatural" phenomena, and demons have not escaped.