Sebastian Aho
Aho will become a group 6 UFA on July 1. He didn't play enough NHL games in his career for the Islanders to preserve his RFA status so he will be free to sign with another club.
Of course, he could sign with the Islanders which is why he makes this list. It's not a given that he will leave, but there's a strong possibility he might leave the only NHL team he's played for since being drafted in the fifth round of the 2017 draft.
I can't say I'd blame him for wanting to leave. He's played 61 games since being drafted and averaged 16:14 of ice time in that time. He's not really making an impact at the NHL level. Or even being given the chance to make an impact at the NHL level. At least not consistently. He might have a better shot at having a bigger impact somewhere else.
Maybe he just decides it's better for him to head back to Europe where he could very well be a top player in his native Sweden.
But it seems, and the entire point of this post, that Sebastian Aho's time with the New York Islanders could very well be over.