To the horsefolk, there is nothing more valuable than their horses. Their lives and livelihoods depend on these animals. Anyone who owns a horse knows that they are flighty, easily panicked, and even easier to hurt. The horsefolk will use their magics to help protect their animals, and will make charms and amulets for them. As rings, necklaces, and phylacteries are either worthless, or completely impractical, they found another way. The charm, or amulet is woven into the mane of the horse, and from there imbues it’s power.
There are likely hundreds of possibilities for Horse Brass, but I think that a horse should be limited to only being able to wear two Brass at a time, like rings.
Earth Charm: a large piece of brightly polished copper that acts as a Ring of Protection +1. Keeps legs from being broken in holes, fly bites to a minimum, and reduces cuts scrapes and bruises from fighting / biting other horses
Wind Charm: A piece of silver, sometimes set with a blue topaz. This charm increases the horse’s overland speed, some more powerful versions doubling, or tripling it’s speed.
Water Charm: Protection from Disease, no more giant snotty noses, or cholic from eating too fast. Their are two kinds of horse, there are healthy horses and there are dead horses.
Fire Charm: Protection from fear, with this charm the horse is steadfast and resolute and doesn’t shy from monsters, sudden noises, or other things that cause a horse to buck, rear, or run away. Undead, and other obviously magical creatures might or might not be affected by this charm. Thus a charm versus undead might be required to keep the horse from being skittish around zombies and such.
Horse Brass was inspired by the Gypsies who do weave bits of metal and glass into the manes of their horses for luck and protection.
Gypsy gold shines in the sun, and whickers in the moonlight.
Additional Ideas (6)
Offers a stronger intuitive and emotional bond between the horse and its master (both must be willing, of course, and it will take some time to master). Both will know fast, what ails the other one, and seem to have those strange "Lassie" moments, as they suddenly sense there is something not right with their friend, even if miles away. Rules-wise this is almost telepathy.
Cooling Touch Charm: protects horse against extreme heat, and fire, magical and mundane
Jove's Favor: tin charm shaped by a lightning bolt that protects a horse primarily from natural lightning, but also potentially from lightning based attacks. In real life, lightning kills quite a few horses and cattle a year.
Hermes' Blessing: gold charm that grants the horse magic resistance, and perhaps immunity to cantrip level magics.
Vulcan's Steed: This large iron charm in epic fashion renders the steed invulnerable to iron weapons. Such things clatter off of the animal's hide like twigs.
This tumb sized piece of tourmaline set in copper wise is braided into the horse's forlock so that it lays against the center of their head. This potent charm causes that horse's coat to change color to match the predominant color in the area. In a forest, the horse would turn a dark green, sandy brown in the desert, or all white on a snowy tundra. Rumors abound of a more advanced version of this charm that allow for multiple colors to be emulated.
Much like the chameleon charm, this string of three pieces of quartz string together with braided horsehair causes the horse who wears it tied to their mane to match the color pattern of the horse that provided the hair in the charm. If a black horse provided the hair, the the horse wearing it becomes black. Patterns for appaloosas and paints are not copied exactly, but are fairly close.
Not every rider can handle a warhorse or a spirited stallion, but putting this small pewter and ivory charm on the mane has the effect of calming even the most virile and enthusiastic of horses enough that even a milkmaid could ride him.
The mount can see better when there is little light and can ride more safely. Now that its radius of sight is larger, it also tends to be more easily spooked by nightly movements and sounds.
The horse always enjoys sound sleep, making it a better ride throughout the day. It tends to be quite a sleeper, however, and is very slow to wake if woken prematurely.
If both are used at once, the downsides do not apply.
A tiny dog statuette, with bits of fur from several trusty dogs, will make a horse more aggressive towards anyone save its owner. It may be able to alert those nearby of anyone approaching, and will probably throw down anyone attempting to ride it.
Horses with a bad attitude will be very hard to control and were seen to turn on their owners if mistreated. The chance to be killed or injured by this horse is much higher, so beware.