I agree with Avna. Bright colors almost universally look good on most horses. I'm a big fan of bright blues with bays, so Thunder the Shire wears blue. Appaloosa Dreams is a loud colored horse, so I chose a loud color for him too - he looks good in vibrant purple. I've always been a fan of bight greens or blues on a chestnut Ö but I also like yellow and red on a chestnut.