The Ranch of Rivershine: Complete Coat Guide

Currently so far breeding works with same sorted groups as here
for example:
Two chestnut parents may produce flaxen chestnut baby
Bay dun and red dun may produce black dun baby
Two black silver maybe produce bay silver baby
Blanket appaloosa and snowflake appaloosa may produce leopard, snowcap or few spots baby

bay and dark bay

flaxen chestnut and chestnut

red dun, bay dun and grulla (black dun)

tobiano and tobiano with ink spots

A fully white coat, has the same colour as white pattern markings. Horses with Dominant White coat in game might have hidden patterns as well, which they can pass on to their foals.

strawberry roan (chestnut roan), bay roan, blue roan (black roan)

Bay, dark bay and black
Silver is affecting bay and black horses manes and tails by turning them white.
Seems like “silver” is a group as a whole in game considering breeding

Blanket, snowcap, leopard, few spots, snowflake or birdcatcher

Buckskin was available in the demo.
It will be a wild horse exclusive (most likely referance to Spirit: A Stallion of the Cimarron)

White splash had various patterns avilable in the demo, most likely will be a wild exclusive pattern

Unknown
Was available in the demo

Unknown
Appeared as NPC horse in the EA

Thanks to Shiro for his excellent guide, all credits belong to his effort. if this guide helps you, please support and rate it via Steam Community. enjoy the game.