Link to description of each of these colors and patterns: [link]
Horse colors, variations, dilutions, patterns, and markings. Information compiled by me from all over the place. I drew the horse outline, colored each horse myself, and arranged them in this classy chart for your reference.
There are obviously subtle and distinctive differences in many of these colors; I chose the ones that fit the description best. Some colors were almost impossible to find pictures of, so I went of my best guess.
I used Wikipedia as a starting point, but the actual information came from other sources. Since much of this research is ongoing, information may change.
The Enclyclopedia of Horses & Ponies by Tamsin Pickeral
Color Genetics: [link]
White Horse Productions: [link]
Horse Color: [link]
UC Davis: [link]
Very, very simple rundown of colors (check the top link above for an expanded version):
Base colors are black
black - red = black
black + red = bay
red - black = chestnut
There are two variations on bay, seal brown and wild bay.
Seal brown basically means the black is less restricted by the red. Thus a darker horse.
Wild bay is the opposite; the black is more restricted. Thus a lighter horse.
Bay is also given different names by shade. Light bay, blood bay, medium bay, mahogany bay, or black bay are all different shades.
There are shades of chestnut as well, including: light chestnut, medium chestnut, liver chestnut, flaxen chestnut, etc.
Pangaré is a lightening of the body and legs can can show up on bays or chestnuts.
Black, bay, and chestnut can be affected by dilutions that lighten or otherwise change the basic color of the horse.
dun + bay = bay dun, dun, zebra dun, or yellow dun
dun + chestnut = red dun, fox dun, apricot dun, or claybank dun
dun + black = grullo(-a), blue dun, mouse dun, or black dun.
cream + bay = buckskin
cream + chestnut = palomino
cream + black = smoky black
double cream + bay = perlino
double cream + chestnut = cremello
double cream + black = smoky cream
silver + bay = silver dapple bay, taffy bays, flax bays, or silver bays
silver + black = silver dapple black, chocolate silver dapples, or silver blacks
(Silver does not affect red hairs so chestnuts are unchanged visually.)
champagne + bay = amber champagne
champagne + seal brown = sable champagne
champagne + chestnut = gold champagne
champagne + black = classic champagne
Pearl is a recessive trait and needs both genes to show.
pearl + bay = bay pearl (no show)
pearl + chestnut = chestnut pearl (no show)
pearl + black = black pearl (no show)
double pearl + bay = bay double pearl
double pearl + chestnut = apricot pearl
double pearl + black = black double pearl
Dilutions can very rarely double up in a horse and affect the color further.
Dun + Cream
dun + cream + bay = dunskin, buttermilk dun, or buckskin dun
dun + cream + chestnut = dunalino, yellow dun, or palomino dun
There is no single cream affect on grullos.
Dun + Double Cream
dun + double cream + chestnut/bay = cream dun, cremello dun, lineback cremello
dun + cream + black = smoky grullo, silver grullo, smoky black dun
Dun + Champagne
dun + champagne + bay = amber dun
dun + champagne + sable brown = sable dun
dun + champagne + chestnut = gold dun
dun + champagne + black = classic dun or classic grullo
Cream + Champagne
cream + champagne + bay = amber cream or buckskin champagne
cream + champagne + sable brown = sable cream or brown buckskin champagne
cream + champagne + chestnut = gold cream or ivory champagne
Double Cream + Champagne
double cream + champagne + any = double-cream champagne
Double Cream + Silver
double cream + silver + bay = silver buckskin
double cream + silver + black = silver smoky black
(Chestnut is not affected.)
Champagne + Silver
champagne + silver + bay = amber silver
champagne + silver + black - classic silver
(Chestnut is not affected.)
There are further combinations, but with each gene being so rare it only multiplies the difficulties of having more than one. DNA testing is necessary to determine the precise colors.
A horse can be any color, but if the grey gene is present the horse will slowly turn grey over time.
Variations on names:
steel grey, iron grey, or salt and pepper
light grey or white grey
flea-bitten with bloodmark (bloody shoulder) as a heavy concentration
Gene-Specific Marks and Patterns
Roan is a mix of white and colored hairs. Also called classic roan or true roan.
roan + bay = bay roan
roan + chestnut = red roan or strawberry roan
roan + black = blue roan
piebald (non-US) - white and black
skewbald (non-US) - white and any other color
tricolored (non-US) - any three colors, usually bay and white (white, bay, black points)
tobiano - rounded, vertical markings
overo - pinto, but not tobiano -- irregular and horizontal
frame or frame overo - horizontal patches with jagged, crisp edges
splashed white or splash - hoirzontal markings with crisp, smooth edges
sabino, sabino-white, or sabino overo - slight spotting with patches of roaning
tovero - mix of tobiano and overo
(Seriously, search for pictures of these, they're impossible to describe.)
Name variations (look up pictures).
blanket or snowcap
blanket with spots
few spot leopard, fewspot, or white-born
Appaloosa roan, varnish roan, or marble
roan blanket, frost, frosted, or marble
roan blanket with spots
solid (no show, but carries gene)
Other Marks and Patterns
Chubari spots or Tetrarch spots
Birdcatcher ticks or ticking
reverse brindle or white brindle
lacing, giraffe markings, marble, cobweb, lace, or catbacked
Bend-or spots, Ben d'Or, smuts, or grease spots
strip, stripe, or race
bald face, white face, or apron face
sock or boot
fetlock, sock, or boot
(If you know of any other name variations feel free to tell me - a lot of people (including myself) have been confused with which names I'm using, since there are bunches.)
This is only meant to be a starting point - to get you an idea of what color you like to make your horse. Please, please check the links above for pictures, and the first link for more detailed descriptions.
Furthermore, these descriptions are still being determined, discovered, and are wildly varied from country to country and even state to state. Currently, there is no set standard. Please consider this before claiming that I have made a mistake. I only put together the research. Thanks and enjoy!