Maybe look for a wide leg trouser in a dress fabric that has some weight or structure to it? Navy is a neutral so you can go as bold or as conservative as you'd like. For bold options check out Eva Franco and Anthro. For more conservative Talbots or Boden.

FWIW I would also try on the top with all of the pants you own to help you narrow down the cut/style you like the best.

Black or brown faux leather pants or coated denim are great for a dressier look than regular denim and just as comfortable. For something like a NYE party I might even look for metallic faux leather/coated denim.

Grey or silver and navy work well together…

I bought it with a very dressy matching skirt, but I think I can use the top as a separate going out kind of top. It's tough to descrbe, but sort of a cape style with a little beadwork at the collarbone. I was thinking fitted black jeans might look good. What else?