21 Minor Spirits your players might run into

Spirits live everywhere.

They're not like spells. Spells are from another realm, scintillating with power; these things were just born in the mud and the dirt and the trash. They arise out of the structures of their place the way human minds arise out of the structure of the brain.

Spirits are magical and mysterious. Most of them come out at night, and they possess an odd ability to go unnoticed even when taking shape. They vanish if spooked or attacked, and might leave you with curses. They probably can talk, but just don't.

A bridge spirit hiding in the water. By Theodor Kittelsen.

SPIRIT HP 1 Def 0 Movement 13 (but can vanish at will) Attack 0 Intelligence 10 Reaction 10 Morale 0. Cannot be hurt by physical weaponry. If a spirit is destroyed with magic, it simply reforms in 1d6 days unless it is driven away by dispelling, or if the place it is bound to is destroyed.

They're like gods, but really puny. Each well spirit is THE well spirit, if you catch my drift. They're both less and more than individuals. They're less in that they are more like natural things, such as rainbows or earthquakes or trees, but more in that they are multiple fragments of the *concept* of the thing they are bound to, such as home. They aren't just a creature tied to a place or object. They *are* the very notion of "home" themselves.

All of them are shapeshifters and not bound to a physical form, but one shape is the default one, their "chosen" shape. But they might as well be that passerby that asked you that really strange question.

A spirit of dead alleys

d12 Village & City Spirits

1. Spirit of dead alleys. Appears as a small and emaciated goblin, nutbrown skin. It searches through trash in order to make a nest for itself. 
1. You can gain its favour by leaving something soft for its nest; if you do, the dead alley might not be so dead at all. 
2. If you offend it, it curses you with No Sense of Direction. The party is twice as likely to get lost.
2. Hearth Spirits. Tiny beings alternately aflame or made from soot; some look like little women in dress and cloak, others like formless blobs with eyes and mouths, others like salamanders. They live in and around hearths and braziers. People leave out food and milk for them.
1. You can gain its favour by feeding the fire or making loud noises of satisfaction from the welcome heat; if you do, rolls to ignite light sources or set enemies on fire will always succeed for 1d6 days.
2. If you offend it, it will curse you with Clumsiness Around Fire. What's that smell? It's the end of your cloak in the fire.
3. Spirit of trash. A small, transparent formless being with huge, luminous eyes. It is born in trash heaps.
1. If you gain its favour, perhaps you'll find something worthwhile in the trash...
2. Offend it, and it curses you with Trash Attractive. Somehow you always get splashed on, dumped on, and find yourself tripping to go face-down in mud and trash.
4. Spirit of bridges. A blue, frog-like figure with long black limbs and red pin-pricks of eyes between strands of black hair that clings to the underside of bridges or sits, not invisibly, just ignored, next to them. They can be the size of frogs or the size of trolls, depending on the bridge. Still they have this odd ability not to be noticed. Often there are shrines to this one, shaped like ugly frogs as well.
1. Gain its favour, and no ill will towards you can cross this bridge. They'll trip and fall; possibly into the water.
2. Offend it, and you will run into continuous bad luck attempting to cross this bridge.
5. Spirit of rooftops. A cloaked, hooded figure, knee-high. Pale luminous eyes under the hood. At night, they slip into windows to steal your dreams with small scythes made of a strange metal (which is why you forget them). Found on rooftops and inside chimneys and drainpipes by day. Hoots like an owl.
1. Gain its favour, and its invisible assistence will help you with anything you attempt on the roofs. You'll also remember your dreams better.
2. Offend it, and you have a 50/50 chance of random roof tiles falling on you once a day.
6. Kitchen Spirit. A shriveled mouse that walks on chicken legs, clothed in rags. They hide under tables, in corners, and near stoves. Chefs and innkeeps have small shrines to them. The kitchen spirit loves a clean kitchen and morsels of the food prepared there. 
1. Gain its favour, and your food will be free of all rot and poison in this establishment forever, outside for 1d6 days.
2. Offend it, and you've got a one in three chance to get food poisoning in the next three days. Also, any food you prepare has a 2 out of 6 chance of getting burned, being too watery, or otherwise being unsuccesful.
7. House Spirit. A cross between a rat and a squat, furred dwarf with the face of a bearded old man. Live in attics. People leave food and gifts to them, because they safeguard happiness and bar unwelcome visitors or ill luck from crossing the threshold.
1. You can't gain its favour unless its your house.
2. If you desire to steal or hurt the house under the protection of a house spirit, your critical failure range is expanded by 5 while inside the house.
8. Spirits of Crossroads. Almost never takes shape. It is this spirit that binds undead and murderers that are buried under the crossroads. If it takes shape, it appears as a small white-haired woman.
1. Gain its favour, and it will expedite your travels. Any random combat encounter rolled near this crossroads becomes a track or spoor instead.
2. Offend the spirit, and any track or spoor rolled on this crossroads becomes a monster encounter instead. Also, if there's some kind of undead or criminal buried beneath the crossroads, the spirit will release it. It might take it a while to dig out, but it will follow you.
9. Well Spirits. Old hags that live in wells. They mostly appear to small children and scare the crap out of them. This is all in good fun; they won't *seriously* harm children unless they go bad or become angry. Then the well will claim victims. Leave some food or gifts by the well at night to make sure that won't happen.
1. Gain its favour, and water from this well will cause a Fear effect in unnatural creatures or undead who wish you harm.
2. Offend it, and you have a 1-in-6 chance of falling in the well if you drain water from it. The hag down there looks like the lady from The Shining, so don't.
10. Spirits of Fields. Like grass spirits, but domesticized. They look like tiny elfin women with flowing golden hair, hiding among the crops.
1. Gain its favour, and they make harvest easier.
2. Offend it, and it will give you a heatstroke when you're out working in the field.
11. Spirit of Stables. Look like babies composed of straw. They speak to the animals at night.
1. Gain its favour, and horses will trust you quickly for 1d6 days.
2. Offend it, and animals will grow restless around you. Don't get kicked by a horse!
12. Spirits of Ship Bilges. Creepy, hunch-backed slippery beings who hide in the reeking bilge of ships. People might throw scraps down there.
1. If friendly, the ship is less likely to run into storms. Boarding pirates all get penalties on their rolls.
2. If unfriendly, you're more likely to run aground or get lost.

A house spirit comes out at night

d9 Wild Spirits

1. River Spirits. Look like emaciated and extremely hypothermic women with gray, wet hair. They can grant things, such as calm the stream to expedite your crossing, or bring something which has sunk to the bottom. The price for these things will often be a life; commonly yours.
2. Ground Spirits. Tiny gnarled things that live in holes. They tend to steal things; food and shiny stuff.
3. Tree spirits. Don't use if you've got dryads or something. Never take shape; the leaves are their tongues and the branches are their fingers. They are unpredictable and might aid or thwart you for motives unknown to any but themselves.
4. Spirits of Wind. These are actually minor dragons. 
1. Gaining a wind spirits favour makes it likely that the wind will be the right way for you to smell certain encounters for the next 1d6 days.
2. Offending it means that a sudden gust of wind will hinder you at the most inopportune time (like when you're trying to read a map, or make fire).
5. Rock Spirits. Large, land-mark boulders or standing stones will have a spirit. This spirit does not take shape. If you harm or annoy it (by moving the rock) it will start mischief (breaking your tools, starting avalanches).
6. Spirits of Still Water. Rotting squat hags that dwell in dark pools. They wake up if you disturb the water and will try to drag you in, to be her companion in her lair. There's probably loot down there of those she drowned before.
7. Spirits of Grass. See-through, almost formless bipeds that inhabit the tall grass. Quiet and helpful, they will guide people who lost their way (especially if there are tears of frustration or despair). But endanger the fields, and they will make your going tough and exhausting.
8. Spirits of Moonlight. Look like tiny pale people dressed in lotus petals. They only come out during full moon and conjure illusions and make people insane.
9. Mist Spirits. Ghostly women composed of fog that appear in the shreds of mist of dusk and dawn. They lead travellers astray into choking bogs and pools.

A wind spirit (about the size of a banana).