The most common dilute combination is the Dun and Cream genes right now. Likely the reason is because they are the most common dilute genes.
Dun with Cream Phenotype
Horses with both Dun and Cream genes present express dun factors however they can be lighter than Dun horses without any other dilutes. On double Cream dilutes the dun factors can be so pale that they are hardly noticeable. This is the reason why double Cream dilute Fjords can not be registered; pale dun factors and blue eyes. Horses with one Cream allele and Dun have black skin and dark eyes whereas horses with two Cream alleles and Dun have pink skin and blue eyes.
Dun with Craem Colours
As much as names for single dilute coats differ one could say that dilute combinations names range even more. I tend to use the most basic terms for the names listed below.
Palomino Dun: Dunalino, Norwegian Fjord: Gulblakk
Smoky Black Dun: Smoky Grullo, Smoky Grulla, Norwegian Fjord: Gra
Smoky Seal Brown Dun: Smoky Brown Dun, Sealskin Dun
Buckskin Dun: Dunskin, Norwegian Fjord: Ulsblakk
Cremello Dun: Lined Back Cremello, Norwegian Fjord: Kvit
Perlino Dun: Lined Back Perlino, Norwegian Fjord: Kvit
Smoky Cream Seal Brown Dun: Smoky Cream Brown Dun, Sealino Dun
Check out the Dun plus Cream album to see pictures of horses with both the Dun and Cream gene: