Ornaments take many different forms, from a simple round ball to highly artistic designs. Ornaments are almost always reused year after year, rather than purchased annually, and family collections often contain a combination of commercially produced ornaments and decorations created by family members. Such collections are often passed on and augmented from generation to generation.
Santa Claus is a commonly used figure. Candy canes, fruit, animals and snowflake imagery are also popular choices
Lucretia P. Hale’s story “The Peterkins’ Christmas-Tree” offers a short catalog of the sorts of ornaments used in the 1870s:
“There was every kind of gilt hanging-thing, from gilt pea-pods to butterflies on springs. There were shining flags and lanterns, and bird-cages, and nests with birds sitting on them, baskets of fruit, gilt apples, and bunches of grapes.”
The modern-day Christmas ornament was originally invented in the small German town of Lauscha in the mid 19th century. (Source)