Here's another very easy Moon, but one that's so out of the way you might've missed it.
In Cascade Kingdom, there's a pair of Binoculars right next to the Odyssey's landing point. Looking through it, you'll be able to see two HatShips flying in the sky -- but you may notice one looks a little off. Zooming into the second HatShip reveals that it's just a Sphynx with a sail, and you'll receive a Moon as a reward.
Finding this Moon required another Google search from me, and I couldn't believe it when it worked. Another excellent example of just how much thought Nintendo put into hiding these Moons!