Depending on where you live, there might be a restoration kind of warehouse that might take them. They aren't vintage or anything, but sometimes those places take newer items. Often the market for used newer bathroom stuff runs about as hot as used stone countertops. You could also try FB or ND, you might find an easier time of someone willing to come pick it up.

Try Chairish. Or find an auction house — search on auction high end bath

Craigslist and FBMarketplace are always good starting places. Since NextDoor is free, why not? Use good pics, link to online sites that show the original price, and be sure your text has the keywords buyers might use to search the sites. And be realistic about prices. You can always donate them to a rebuilding center or Habitat for Humanity store.

You might be financially better off taking the tax write off by donating these than by attempting to sell them.

As others have posted, realistically your market is going to be limited to those within your geographical area because it is unlikely that anyone is going to want to paying shipping costs and have to deal with issues that might arise.

Realistically these are used items and the stars and the market for used fixtures is limited - and those woud be people seeking bargains. Seems like a lot of trouble for not much economic reward.

Of course if you have ample storage room you can just keep them until the right buyer comes along.

I looked up those items and now I understand why you are interested in selling those fixtures. It just boggles my mind that someone would pay that much money for a bathtub.

List them on ebay for local pickup. There are six bathtubs and two sinks on the site now.

Do people who can afford those fixtures care about bargain shopping? Would they even be looking on CL or ebay for fixtures? I doubt it. People who appreciate the quality but could never afford them might be interested, but even half price may be way out of their budget. But you never know until you try!