Royal Blue, red, orange. There are so many colours. But is your horse a lighter or darker bay? :)
Light blue burgundy white
Hunter green, burgundy, teal
White, hunter green, or black
A color that compliments the horse. If the horse is darker I would say a blue(any shade) but if it's lighter then maybe burgundy, green, or red
All colors look great like purple, pink, yellow, orange, teal, green, mint, etc
If it's a light bay I'd go for dark colours (navy, bordeaux, dark green), if it's darkish I'd say bright or pastel colours
Almost at bright color, teal, pink, red, yellow, purple, light blue, etc...