Frank J. Wilstach, comp. A Dictionary of Similes. 1916.

Unexpected

Fortune came like Agag, unexpected.
—Anonymous

Unexpected as chastity at the bar of a tavern.
—Anonymous

Unexpected, like a thunderbolt.
—Anonymous

As unexpected as a serpent comes.
—Robert Browning

Unexpected as seeing a vision.
—Joseph Conrad

Unexpected as a fifth ace in a poker deck.
—Alfred Henry Lewis