Most sheet sets typically include a flat sheet, fitted sheet, and one or two pillowcases. There’s not much need for wondering if you need a flat or fitted sheet for this reason — both are useful and usually come as a package deal. Some other sheet sets, like those Casper offers, also include a duvet cover. 

Throw
Luxury throw blankets are small decorative blankets, often with trim or fringe, that are used for extra warmth, decoration, or as a covering when lounging on top of the bed. It is normally folded at the foot of the bed, on top of any other bedding.