Do Not Buy a Toilet Cover Rug Set
This is a trend that is both unsanitary and unsavory. Plush toilet seat cushions are havens for bacteria and mold in wet environments. Additionally, who's sitting down on the top of the toilet long enough to justify needing a cushion?
Here's an Alternative
Instead of buying a matching rug set for your toilet seat and the floor, just buy two separate rugs, Place one rug in front of the shower (you know, to collect water drippings), and place the other in front of the toilet. Your bathroom shouldn't be the most relaxing place in your home (arguably), and keeping it neutral is the best way to get the job done quickly.