A Goat is an animal usually use as live stock.
The Heroes of Olympus
The Demigod Diaries
The Diary of Luke Castellan
When Luke Castellan and Thalia Grace are in Richmond, Virginia, they find Amaltheia and follow her to an abandoned mansion.
Magnus Chase and the Gods of Asgard
Thor's goats, Marvin and Otis, appear in two of the three main series books and in one short story in 9 from the Nine Worlds.
Magnus also bumps into a goat named Theodore in the book 'The Ship of The Dead'.