Canadian NDP - Probably in a better state than most on this list due to the realistic possibility (this IS Canada after all) that they could win the next federal election with 68% of the vote and all but two seats. Still, pretty sucky that, after decades of effort, their time in OO was so brief.
It is Canada, but the chances of the NDP winning the next election are next to nil. It's hard to predict what will happen right now as they are leaderless, though. I think right now only someone like Jagmeet Singh could save the party (a minority, charismatic, young) in the near term. Of course, nobody knows who he is now, but he is a rock star in the making.