Common covers include 100% cotton, cotton blends (for example 60% cotton/40% recycled polyester), cotton blended with lyocell, and cotton twill (often ~230 thread count) used on euro-style pillows.
Common options include soft, medium, medium/firm and firm, covering a spectrum from softer, sink-in feels to firmer support.
Typical sizes are standard, queen and king, plus decorative euro-square sizes (for example 26"×26"); product listings usually show these common dimensions.
Listings typically highlight hypoallergenic construction or an allergen-barrier on the cotton fabric to limit common triggers; manufacturers often label the cover or pillow as hypo-allergenic to indicate these design features.
Review summaries frequently praise machine-washable construction, easy-care instructions, and the ability to quickly reshape or fluff the pillow after unpacking.