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

Harmless

Harmless as a strawberry festival.
—Anonymous

Harmless as Sancho’s ass.
—Anonymous

Harmless as the turtle-dove.
—Patrick Brontë

Harmless and pleasant as the murmur of brook and wind.
—Robert Buchanan

Harmless as an infant’s play.
—William Cowper

Harmlesse as the bee that doeth but taste the flower and flee away.
—William Drummond

Harmless as reptiles kept in spirits.
—Sydney Munden

Harmless as the turtle of the woods.
—Thomas Otway

Harmless as a paper tiger.
—Chinese Proverb

Harmless as my life’s first day.
—Algernon Charles Swinburne

Harmless as the lightning life of song.
—Algernon Charles Swinburne

Harmless … as petals of a flower.
—Bayard Taylor

Harmless as doves.
—New Testament

Harmless as a babe.
—William Wordsworth