Unique company or business ideas

I am looking for unique companies that have a continuity (e.g. subscription plan or auto-ship) business model

* Definition of Continuity Businesses:
Sales made in series, small amounts or periodically rather than one at a time. Usually a set of products/services with a common theme (books, records, collectibles, etc.). Basically, continuity businesses expend only an initial selling expense to generate periodic and regular revenues over time.

* Any and all ideas will be greatly appreciated! Again, I am looking for actual companies. Thanks!