Sometimes, tortoiseshell cats can have tabby patterns in a single or both of those colors. A grey tortoiseshell cat or a tortoiseshell tabby cat, called a torbie, can sometimes have a novel color pattern named mackerel. I've a Mackerel Torbie and didn’t recognize it right until I read through this https://tortoiseshell-cat67899.thelateblog.com/34412408/5-simple-techniques-for-tortoise-couleur