Gonne's nickname, at least in the American papers, was "The Irish Joan of Arc." Check out this article from 1897 describing her visit to America (source).
Gonne appears in a not-insignificant amount of Yeats's poetry. Here she is in "The Old Age of Queen Maeve": "Fashioned to be the mother of strong children;/ And she'd had lucky eyes and a high heart./ And wisdom that caught fire like the dried flax./ At need, and made her beautiful and fierce,/ Sudden and laughing."
Maud Gonne gave Yeats a notebook in 1908 that he kept for the rest of his life. The notebook records how both he and Gonne were interested in the supernatural and occult (source).