I have been looking for a nice set of....

I use a set of floor mats from mustangs unlimited that are black carpet with the cobra snake embroiderd in it......

 

My preference is for the period aftermarket Mustang pony floor mats with the white stripe. I several years ago I purchased two sets of these mats; NOS, black / white stripe. Being NOS the white stripe has a hint of aging / yellowing. In the evening when I open the door and the underdash lights illuminate these mats with stripes ... I love the way they look. A little over a year ago some firm started to reproduce these mats in several of the original colors (black, blue, dark red .... all with the running pony and white stripe). I am certain you can find several parts suppliers selling them. Otherwise - Search eBay for "Mustang mats". You will find multiple sets offered; all colors.