Kelly McCrimmon has been clearing the deck for something big, but his trades are often quite unusual, e.g., getting Eichel during the neck surgery controversy or taking Hertl coming off an injury. A big McCrimmon deal will come out of left field and probably nobody will foresee it.
McCrimmon might try to bring Marchessault back for the playoffs. Marchy really didn't work out that well in Nashville, Vegas wanted to re-sign him but Nashville offered an overpay that McCrimmon could now bail them out of, and Marchy would fit back in like a glove.
IMHO, a problem this season is that so many East teams are still arguably in the WC hunt that there may be fewer sellers than usual, plus, with the cap going up so much, teams might feel more comfortable in their ability to re-sign their quality FAs.