Having written quite a lot of fiction in which a climatic point is when the person being enslaved has their full name stripped from them and they are forced to accept their slave name, what I usually call their 'collar name', I have followed this discussion with interest. In terms of fiction, it is easiest to have all the slaves featured with different names, though they may be addressed as 'slut', 'pet', 'cunt', 'slave', etc. In some ways this is a reference back to Roman times, as a citizen would have three names but a slave only one and I find this change for someone from e.g. 'Sarah Jane Smith' to simply 'Lyra' very arousing.
I am always on the look out for suitable slave names, and ones with sibilants in, always appeal to me, like Syntessa, Larissa, Syra, Fush, Lyssa etc., so do 'l's especially if pronounced in a full-tongued Britney Spears pronunciation, e.g. 'Limara', 'Layla', Jilail. 'y's always seem more exotic, so I have used 'Tyta, 'Jyla', 'Cypha'. Names ending in 'a' also seem to have that feel, again because Latin names ending in an 'a' are feminine, and the word for a female slave was 'ancilla', so I have used Cella, Dalia. For chracters like ponygirls, like many writers, I have used pet sounding names, with 'Arabella' and 'Chantelle' and 'Troy' for a ponyboy.
I agree with Mobius's list of sub-sounding vanilla names and will raid that in future, I trust that is alright? Though Holly always sounds too harsh for a slave name, and I cannot shake the image of Holly Martin (a man) in 'The Third Man' movie, though Harry Lime from the same film (and the book) is a good Master name. There are also bimboesque names, notably 'Kelly' and 'Sharon/Shaz'. Names that in North America are seen as ordinary like Sharon and Tracy, have a real bimbo association in the UK.
For Dom/me names, I agree about the Slavic, multi-syllable names being appropriate. Also medieval sounding names, like 'Eleanor', 'Millicent', 'Illaria' (an Italian name), 'Syltera' have the sort of weight, but often Masters and Mistresses are simply known by their surnames, Harrison, Nash (partly influenced by the blond male assassin in 'From Russia with Love') and Edison are three I have used. I have used 'Cazine' on a number of occasions. 'Petra' sounds like a Mistress's name, but I have used 'Petrina' for a slave name because of 'pet' in it.
I think there is an importance in the way the names are to be said. A Dom/me's name should be able to be spat out like a command, and a sub's name should be able to be said in a seductive way, sapping their will and leading them deeper into their slavery and recognition that this is their new true identity. Just my tastes.