There are plenty of discontinued Mikasa dinnerware patterns. The company has lived through many trends since the founding as a dinnerware importer in 1948 under the name, American Commercial Inc. In 1957, America was introduced to the brand name, Mikasa. Now it is a division of Lifetime Brands, Inc.
A great way to find discontinued patterns is to search for the pattern name on an online auction website.
If you don't know the pattern name, you can sometimes find it by searching for vintage dinnerware or antique dinnerware.
When I entered "vintage Mikasa" in the search box on eBay, over 1,400 results came up and the selection was amazing. There were full dinnerware sets, discontinued pieces, dinnerware pieces, teapots, figurines, crystal goblets, decanters, sugar and cream sets… the list goes on and on. The styles range from retro to modern.
The term "antique Mikasa" brought up fewer selections, and of course, the currently produced pattern of Mikasa Antique White came up because that is the name of the pattern. There were some selections under that term that didn't come up under vintage.
The term "discontinued Mikasa" produced several results as did "retired Mikasa".
There are several replacement companies that are highly recommended. Probably the most popular is replacements.com. They have an awesome collection of discontinued dinnerware and you can register the pattern or piece that you are looking for with them and you'll receive notification when it is available.
By typing "replacement dinnerware sites" in your browser, you can discover multiple replacement companies that might have or can help to find exactly what you are looking for.
Mikasa has excellent customer service. If you are looking for a recently discontinued pattern, check with Mikasato see if they have it. If they don't, they might have some suggestions for where to find it.