From the current NHL roster? There really isn't much the Blues would move that would likely be of interest. Barbashev, Bouwmeester, Gunnarsson, Bortuzzo, Berglund, Sobotka. Maybe Steen in a bigger deal. There isn't much surplus talent at the NHL level on this team right now. Fabbri isn't out of the question, but he's such a question mark given his last two years of injuries that his value is pretty unknown.
I think a futures package is the best option for the Blues right now, all things considered.