I've been looking at what other colours are used with black in clothing of that time - where black is the dominant colour. I was disappointed to mainly find another black fabric (satin or velvet), or gold or white, neither of which really suit me. (gold especially). I don't want to work with either satin or velvet so we can scratch those options. The only other one I've found has been in a couple of spanish garments, which have blue, for example this dress in the Museo Traje in Spain. (and I'm sure I'm spelling that wrong but need to put laundry away not spend another how down the rabbit hole of the interwebs. They have a black jacket with similar blue so although I'm not making a spanish dress per se, it's my rationale for my choice.
In addition, there was a fashion plate on Lara Corsets of a bonnet of black & light blue.