So, I may not be of much help here, but I have always preferred slaves/subs to be nude. I guess it's due to getting first seriously started into kink by "The Claiming of Sleeping Beauty", where pleasure slaves wore nothing, ever.

That said, I have become a fan of naked slaves in decorations. jewelry- not just collars, but body chains, necklaces, loops of thin chains draped over shoulders, down breasts , that sort of thing. Nipple rings with chains, pearls around the genitalia, or even a butt plug with a jeweled or carved end for decoration.

It sends a message- that the master/mistress could afford to dress the sub properly, but chose to drape jewelry upon them that specifically hides nothing.

if this piques your interest, check the following subreddits:

https://www.reddit.com/r/justthejewels/

https://www.reddit.com/r/NothingButNecklace/

Barring that, I've always been a fan of the Slave Leia look. Variations on that are always appreciated- different colors, open bra revealing the breasts, shorter loin cloth, sheerer material, etc.

if you are going for a lingerie look, I have always been fond of this look. It's from a Hajime Soryama painting, this is a sculptre based upon the original painting:

https://www.e2046.com/gallery/view/14951

Good luck!