Dowsing Rod (Detects materials or individuals)
A split length of wood with an internal chamber of half a thumb's size. When a substance is placed within the chamber, the rod will point towards the nearest source of that substance. This property can be used to find specific individuals, so long as the user is in possession of the target's name and some part of their body.
Dowsing rods may be found in the possession of witches, hedge wizards, and other magic users.
Shamble (Detects worked magic)
A makeshift device of twigs, string, and whatever's on hand that can detect nearby human-worked magic. A trade secret of witches.
Shambles are temporary things, and cannot be bought. One might, however, be able to persuade a witch to teach them the craft of it.
White Leech (Detects disease)
Turns a foul brown-red color when feeding upon those with a severe bacterial or viral infection.
A dose at the local barber's costs 5s.
Bezoar Powder (Detects poison)
Low-quality bezoars are ground up into a powder that can detect, but not cure, poison. If sprinkled upon or mixed into a poisonous substance, it will let off a pinkish smoke.
A bag of bezoar powder, enough for 3 uses, costs 50 silver.
Canary in a Cage (Detects poison gas)
Dies when exposed to toxic gas. Depending on the toxicity of the gas, players will have to resist effects immediately, or in 1d6 turns.
The wicker cage costs 5 silver, the canary 10.
Dog or cat (Detects ghosts, Folk, and other spirits)
The easiest and most reliable method, though it is likewise the broadest and least specific. Prone to false alarms triggered by the mailman or the feline desire to fuck with people.
Common pets cost 1-10 silver.
Soulwood Bough (Detects angels and demons)
A length of fragrant, silvery wood. Blooms white in the presence of angels, and black in that of demons.
Can be found in the possession of some magic-users and priests.
Angeldown (Detects evil spirits)Delicate white feathers that will catch with brilliant gold-orange-blue-white fire when in the presence of a demon. Evil spirits trapped in its light will take an additional 1 damage per turn, per feather.
A single feather costs 50 silver in regions angels frequent, and 500+ silver where they do not.