Are there any spirits that equips either a Hammer or Golden Hammer?

Solution 1:

No, there is no Spirit that equips a Hammer

To complement Toomai's answer for completeness, you can ctrl + F and search through the full list of all 1303 Spirits here for "hammer."

Doing this, you'll find several Spirits that give "Weapon Attack ↑," which includes increasing Hammer power. You'll also find the Spirit you have, Mini Mario & Hammers, which increases the duration of Hammers.

However, it seems those are the only Spirits that have anything to do with Hammers. As of now at least, there is no Spirit that will let you start with a Hammer.

Solution 2:

Yes indeed, the Hammer and Golden Hammer are apparently strong enough items that not only is there no spirit that provides one at the beginning of matches, but the only spirit that touches them (specifically) at all is the singular "Mini Mario & Hammers" enhanced spirit. As a result, the only way its effect will be used is when a hammer happens to appear and you grab it. This makes the effect situational to matches where you know hammers are an active item.