[abecedarius]

Good one. The novel Courtship Rite by Donald Kingsbury had such a moon (the Scowlmoon) as part of the worldbuilding.

For another, imagine having a moon so big it can completely cover the sun... and just the right size and distance to only block the photosphere, leaving the corona visible without instruments. What a show that'd be, what wild myths the life there might make up.