When a yellow light explodes, the 3x3 area centered on its explosion area will be permanently lit up.

Angering peaceful monsters by casting an innocuous spell like light is very annoying, so split the spell up into a “light area” spell, which does not damage anything unless it’s a highly light-sensitive monster like a gremlin, and a “light blast” or “flash” attack spell, which may or may not light the area permanently and is designed to blind monsters.

Cantrips are level 0 spells that cost d2 or d3 power to cast. In order not to let them be unbalancing, they don’t train skill and are mostly useless, except in certain circumstances or for low-Pw spellcasters who can’t do much of the bigger stuff yet. ais523 suggests that good candidates for cantrips might be things that have little combat use, and whose effects could be duplicated by backtracking or other tedious things, but would be useful to avoid boredom. Given their cheapness, they should probably not train skills, and may not even need spell schools.

Most ideas for cantrips seem to be a little too powerful and would do better off as normal spells (and may be listed as independent YANIs for normal spells); however, those that seem like they would fit are listed here.

• Increase the odds of monsters dropping a corpse in the next few turns.
• Create an empty unlocked chest. (This would need some restriction so you can’t farm and sell them; perhaps you can only create up to 10 or 20 chests per game with this.)
• Mark a map square with a symbol, perhaps a comma, that is no different from normal floor but shows up on #overview and the normal map view.
• Deal some small damage, such as d5 or d6, to a nearby creature. (Acid Bubble from D&D is a nice corresponding cantrip.)
• Dig out a single square.
• Create a cancelled hostile yellow light. It cannot explode at you since it is cancelled, so it becomes an autonomous light source of radius 1, which can’t follow you down levels like a pet can. Killing it should not grant you any experience; otherwise this would be easily farmable.
• Light a radius 2 or 3 area permanently, like a weak form of the spell of light.
• Mage hand: you indicate a direction and the nearest item on the floor in that direction, assuming it’s under 100 weight or so, is brought to you and is placed in your inventory. This can be used > to get things out of pits.
• Create an illusion of yourself at your spot. The illusion never moves. Monsters that see it assume it is you and will attack whichever one is nearer (the illusion is instantly destroyed if attacked).

Temples are always lit up; never dark.

Invoking the Longbow of Diana gives you light arrows. These are a special object, weightless, created with the same enchantment as the Longbow, but attempting to enchant them further will fail (maybe making the enchanted arrows evaporate). If they leave your inventory for any reason, they will vanish. As a weapon, they are very powerful (to the point of probably instakilling most weaker monsters they hit). To prevent the player stockpiling them, the invoke effect will only top up the amount of them in your inventory to 5.

When a light arrow strikes a target or falls to the ground (and vanishes in the process), it permanently lights up the surrounding area.

When a light explodes, it permanently lights the terrain in a small radius centered on it. Black lights might only light in a radius of 1, or just its own space.

In the Big Room variant that has squares of light and darkness, make the lit regions circular rather than square (possibly by scattering candles and lanterns on the ground, or just by making random circular spots of light).

The Astral Plane should be brightly lit, what with having all the halls of the gods and being suffused with holy power.

Instead of being completely lit or unlit, Mines levels can generate with large contiguous areas of lit and unlit floor.

A blessed scroll of light lights up the entire level.

Give Sunsword an invoke effect that creates permanent light in a radius like the wand of light. “PRAISE THE SUN” optional.

Magical sources of light that light up a fixed area are temporary, and revert to darkness given time.

Fire trap effects, fire explosions, and camera flashes light up a large area, but only momentarily, before it goes back to darkness.

Elves get low-light vision, which doubles the radius of light sources, rather than infravision. It also gives them vision on dark squares that are orthogonally or diagonally adjacent to a lit square.