Yggdrasil: I seriously just have no idea of what strategic use this might have. Particularly late in the game, since it sounds like it'd just cover most of the board in random units which would then go randomly berserk at each other.
Fenrir: Havent needed to kill a god. Even moreso now that they do not defend areas with crazy attacks, this is totally useless.
Brokkr: The Norse pretty much already have a powerful "decrease/remove cost" ability in Norns, so this is kinda redundant, and also by the time I could really pay his cost, I probably just dont need it anymore.
And it's not a "token", but I still have no use for the Elf. It's weaker (by quite a bit) than the Ice Giant, and it's ability simply does not make up for that. Valkyrie is pretty much the same here. I pretty much stick to just the giants and trolls.
Hebe: I've simply never had a need for it.
Labyrinth: Not entirely sure on this one. I havent unlocked the ability to actually use the minotaurs yet, not without Cornucopia in play, so I've never touched this. But it seems like I'd need quite a number of those guys in play before this one would make any sense at all.