Very cool.
Tomb of the Silver Dragon? I already explored that in middle school.
https://i.ebayimg.com/images/g/CyAAAOSwz6RgA9zB/s-l400.jpg
While I don’t see any signs of bridle or tack
I remember seeing illustrations of Step horses
wearing unicorn like fittings.

Silver dragon
Silver Dragon
(Draco Nobilis Argentum)
Silver dragons, sometimes referred to as shield dragons,[8] were a breed of metallic dragon.[3][8]
A silver dragon enjoyed the company of humans and elves so much that it would often take the form of a human or elf and live among them for the majority of its life. However, it should be noted that silvers, like all dragons, believed themselves the most superior creatures in the world. However, apart from the ability to fly, which they enjoyed greatly, they tended to prefer the physical forms of humanoids for everyday life.[8]
Dragons and unicorns....................Maybe they weren’t ‘mythological’ after all..............