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

Plump

Plump as an orange.
—Anonymous

Plump as plenty.
—Anonymous

Plump as a peach.
—Charles Dickens

Plump as ripe clusters.
—Richard Duke

Plump as a pudding.
—Nathaniel Hawthorne

Plump as a cherry.
—Robert Herrick

Plump as a partridge.
—Samuel Lover

Plump as a melon under a glass.
—George Meredith

Plump as mastiffs.
—Plautus

As plump as a miller’s sparrow.
—Scottish Proverb

Plump, like tiny skins of wine.
—James Whitcomb Riley

As plump as plump can be.
—Christina Georgina Rossetti

Plump as stall’d theology.
—Edward Young