Magenta on liver chestnut. Purple or yellow on buckskins

Id suggest purple for chestnuts, my boy looks awesome in it

Royal blue looks absolutely stunning on my real life dark bay

I have a grullo, deep blues and purples look absolutely beautiful on him. Green can also be nice depending on the shade, and I'd steer away from orange or lighter reds though deep pink can be nice.

Chestnuts look good in a vivid dark green or middle shade blue. Purple is also a super good choice for a chestnut.

Also have a bay and she looks very nice in powder blue or any kind of green.

Red duns look nice in blue (again! blue is really good for lots of horses XD) or green. Light purple or light pink is good too.

I ride a black horse and a red dun with dark green saddle pads, white half pads, and a lovely shade of chocolate for the saddle and bridle. :) I think palominos look great in almost anything tbh, but that's just my opinion.

My buckskin mare looks great in lilac, black, gold, teal, and some samon pinks. She doesn't look good in red, dark purple, dark pink, orange, or yellow.

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My bay mare looks great in any shade of pink, purple, black, and some shades of blue. She doesn't look good in green, red, or orange.

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Palominos look awesome in teal, light pink, dark purple, and black.

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Greys look awesome in teal, blue, pink, maroon, green, yellow, white, and red.

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Blacks look good in teal, bue, red, orange, green, purple, and white.

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Chestnuts look good in maroon, teal, blue, red, beige, and white.

i use a light blue or green on my mare, sometimes ill use purple. never put the saddle pad color as the same as their fur, it personally drives me crazy, but it also looks weird.

ill explain orange on a chestnut is a no, black on a black (haven''t seen but feel like that would be weird).

Dun buckskins look stunning in royal blue, hot pink and deep purples.

Dark navy looks stellar on basically anything

I quite like pastel blue, pink, purple and yellow on black horses. It seems to just make them "pop out"