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

Fat

Fat as a bacon-pig at Martlemas.
—Anonymous

Fat as brawn.
—Anonymous

Fat as a sheep’s tail.
—Anonymous

A red bag, fat with your unpaid bills, like a landing net.
—Dion Boucicault

Fat as Mother Nab.
—Samuel Butler

Fat as a whale.
—Geoffrey Chaucer

Fat as a barn-door fowl.
—William Congreve

Fat as seals.
—Charles Hallock

Fatte as a foole.
—John Lyly

As fat as a distillery pig.
—Scottish Proverb

As fat as a Miller’s horse.
—Scottish Proverb

Fat as butter.
—William Shakespeare

Fat as tame things.
—William Shakespeare

Fat and fulsome to mine ear
As howling after music.
—William Shakespeare

Fat as grease.
—Old Testament

Grow fat as the heifer at grass.
—Old Testament