Stun grenades, which work similarly to regular grenades except they explode for zero or a token amount of damage, and inflict stunning and other types of status effects on things in the blast radius. For instance, there could be a flashbang grenade which stuns and blinds its targets.
When the game calls for a message to be shown based on its string id in the quest.lua data file, it also supports running a function that tests whether the hero is blind and/or deaf and returns different string messages accordingly. (E.g. a lot of quest messages describe the surroundings, which doesn’t make sense if you’re blind.)
Archons’ light radius should be a passive aura area-of-effect attack that causes strong light effects: potentially blinding normal monsters, hurting gremlins and undead, petrifying trolls, and so on.
Wielding Sunsword protects you from being blinded by an Archon’s radiance.
In variants implementing a wand of water or other methods of shooting water: a solid creature with eyes that is hit by a shot of water has a fairly small chance of being blinded.
Automatic searching triggers standard 1-radius searches even when the player is blind.
When blind and holding a leash with a pet on it, you can see the pet.
Dart traps can make you fall asleep, go blind, hallucinate, get confused, etc. This would mesh well with #1922.
The spell of light has an advanced form, which is a ray. It blinds monsters it is fired at like a camera flash does. (The camera flash is also transformed into a ray, which can be reflected.) In Wands Balance Patch-implementing variants, the wand of light should also have this effect for skilled users.
Spell of blindness (possibly also available as a wand), which blinds monsters.
Applying a looking glass cures blindness, in some very odd uncommon set of circumstances (like when hallucinating).
Will-o-the-wisps: gray or possibly bright blue y-class monsters that spawn individually, leave no corpse, and have no attacks except a passive blindness attack. They emit light radius 0 so you can see them, but no surrounding squares, across a dark area. Not infravisible, and could have teleportitis to replicate their folkloric effect of suddenly vanishing. Spawn rarely in swamp rooms and may not spawn at all in a lit area. Most importantly, they have a special AI that causes them to avoid the player and orbit around treasure (occasionally) or around hazards like monsters or traps (commonly).
Sunglasses, an eye-slot tool that protects versus being blinded by flashes of light from things like lightning bolts, cameras, and yellow lights, either completely or with an 80% chance. (They probably shouldn’t block blinding from spat venom.) May also block certain gaze attacks. They should have some downside when worn, such as limiting your maximum vision radius or impeding searching.
Tourists start with a pair of sunglasses.
The spellbook of cure blindness can be read while blind.
You can wear an empty bag over your head to blind yourself, but this sets charisma to 6. If you wear an oilskin sack on your head, it starts a strangulation timer. If you wear a bag of tricks on your head, you get YAFM and instadeath, or possibly it just constantly bites your head.
