The largest replacement company makes up pieces. For example, Manchester made ice cream forks in my pattern, which I inherited from my grandmother but they are hard to find. Replacements “hand crafts” them from teaspoons. They do not look exactly like the originals and I regret the loss of those spoons because some day my daughter or granddaughter may lose one in the garbage disposal and a replacement may be scarce due to the originals being cannibalized into other pieces.
If you are talking about Replacements in NC, I know. And they make up things that never were manufactured originally. Wall sconces out of plates. Triple stacked cookie servers, etc.