One guy that I haven't seen mentioned a lot that could be on the block is Pavel Buchnevich.
I believe we were rumored to be on him before he signed his extension last year. I believe it was rumored to involved Broberg and Holloway at the time. It makes sense given that they just waited to offer sheet both of them instead.
Buchnevich is still in his final year of his contract, with his new contract kicking in July 1st. His current contract only has 12 team NTC and is at a more affordable 5.8M contract. However, the extension has a full NTC for 4 years and then goes down to 20 teams in Y5 and 15 teams in the final year.
It might make sense for the blues to move him now if they aren't ready to commit to him until he's 36. His production has dropped since last year with only 11 goals and 34 points in 54 games. The blues were probably expecting his production to go up and be a consistent 70+ point player, not drop down to a 52 point pace.