This image shows a large collection of trivets, metal stands for hot pots, pans and irons. It is part of the collection at Pioneer Village in Minden, Nebraska.

The description states:
COLLECTION OF TRIVETS
One of dozens of unusual collections in the “Hobby House”. Some of the 30,000 items in 22 buildings on 2 1/2 city blocks showing man’s progress since 1830. Located 130 miles west of Lincoln, Nebr., on U. S. 6 & 34.
—Trivets were not only stands for pots, but also for cooking over fires, and for lifting food inside pots when roasting. Those shown here are mainly for table protection from hot pots used to serve food. The arrowhead shaped ones were for irons, which were commonly heated on top of a stove before use, and needed a safe place to rest when they were still hot. This kind of trivet has fallen almost completely out of use.
This image likely dates from the 1950s.