For The Blues I could see any of Buchnevich, Krug, Faulk, or Kyrou. In that order of likelihood.
Buch seems to be the easiest player to move. Top Line 2-way winger with only a M-NTC with a cheap contract (for what he brings) for next season.
Return: 1st round pick at the draft with a + depending on where the pick lands in the draft.
Krug and Faulk are interchangeable imho. I don't think the Blues want to go into next season with them both on the roster, but with them both having Full NTC for the next season I could see them sticking around for that season until it turns into a M-NTC after 01JUL25.
Return: Roster Forward or Defensemen who has fallen out of favor with team.
I think Kyrou is the most doubtful to be moved, but, with how much the STL fanbase and media despises him it wouldn't surprise me if he's moved, but it would need to be something worth while, but. His NTC doesn't kick in until 01JUL25, so I could see the Blues holding on for one more year to see if he can score another 30+ goals to either help his value or left him prove he belongs.
Return: 23-25 year old Top 4 Defensemen swap.