1x in every deck with at least 1 hero who's going to be questing. With a few exceptions, questers typically won't be using their restricted slots, allowing you to slot this in and not have to worry about it taking up a high-competition deck slot. The response is niche, but useful in that niche (it completely discombobulates Aimless Wandering from the Uncharted quests from the cycle, for one), and 1 cost for 1 is a fair trade. With Elfhelm, it becomes incredible, becoming 1 cost for +2 , effectively making it a half-price Silver Circlet.
Attachment. Cost: 1.
Attach to a hero, or to Éowyn. Restricted.
Attached character gets +1 .
Response: After attached character is removed from the quest, exhaust Windfola to commit attached hero to the quest.
...the great grey steed Windfola made little of the burden; for Dernhelm was less in weight than many men, though lithe and well-knit in frame. The Return of the King
A Storm on Cobas Haven #116. Spirit.
A 1-for-1 cost-to-Willpower is always good and since nowadays there are a lot of treacheries that remove character from the quest it can always be useful. It's make the best use of where you can use to boost other stats like with Herugrim, Golden Shield, Fair and Perilous but generally amazing. Of course it can be paired with a Westfold Horse-breeder to fetch it.