A muse.

/myo͞oz/

1.

(in Greek and Roman mythology) each of nine goddesses, the daughters of Zeus and Mnemosyne, who preside over the arts and sciences.

Similar:

inspiration

creative influence

stimulus

stimulation

afflatus

2.

a person or personified force who is the source of inspiration for a creative artist.

"Yeats' muse, Maud Gonne"