Golem factory, Uncommon, 15b
Durable
If Unliving tokens>80
Upgrade rarity of a selected Unliving
Unliving tokens=0
I wouldn't spend bricks on this. Realistically, if I had 81+ tokens, I could play an Uncommon Unliving to trigger the effect and get most of its brick cost refunded as a result. Either way I have 0 tokens afterward, but playing this card would be a loss of bricks for a questionable effect (compared to what playing an Uncommon Unliving could have done).
Even if it cost, let's say, gems instead, I doubt I'd use it. There's simply no room for another Uncommon in a good Unliving deck, and the ideal mode of play has you flipping the token counter every second Unliving card. I suppose having this in hand, Durable as it is, would make it more likely that you're only getting 49 tokens each play, but ideally you're getting 57 on one of the two plays and never ending a turn with more than 64 tokens.
If it were to cost gems (or mixed bricks/gems, or simply fewer bricks) and have the effect occur when tokens are 40+, it might be a consideration, but the fact that there are so many good Uncommon Unliving choices might remain a deciding factor against it.