Simple QoL addition done by request of OpenGrip, allows you to ignite/extinguish all light sources in a radius around you. Very convenient for instantly lighting up dark dungeons and whatnot. Also, you can set the radius to some small value so you're only dealing with the nearest lightsource, except now you won't have to position yourself absolutely perfectly to interact with it.



Usage:
To perform this action, cast igni/aard (to ignite/extinguish, respectively) while witcher senses are active. You don't have to fully enter witcher senses, just quickly tap it + cast sign key. I did this to avoid having to create new keybinds. There are already too many mods that add new keybinds, and too many users incapable of properly editing their input.settings or relying on a mod manager to do it. If you have an instant sign casting mod, this will work with that too. You will be able to perform this action even when signs themselves are not allowed. If you are holding a usable item in your left hand (such as a torch), Geralt will temporarily put it away to snap his fingers, then take it out back again.

Options:
You can adjust the radius from 0-50. For immersion I recommend 15, but maxing it out will make for a convenient experience. If you don't touch the settings at all, upon first using the mod the recommended settings will be selected for you. You can, of course, edit the XML to increase the radius even further, but I don't recommend doing this. There are some nuances when setting it very far, which is why I limited it to 50.

There is also a Fade Lights option. If you leave it off, the lights will toggle on/off instantly. Thought it doesn't make that much of a noticeable difference, I recommend turning it on.

Finally, there is an option to Disable normal interactions. This was a requested feature. It will completely disable the normal Ignite/Extinguish action prompts on all light sources, so that they don't bother you ever again.

Note:
There is a console command- 
lit_firesource(b : bool, optional radius : float, optional dontfade : bool)

It will do the same thing, but only search for the W3FireSource class. This will allow you to overcome the limitations of fetching too many gameplay entities and set a much higher radius. The downside is that only objects like floor braziers, shrine fires, and coal have this class, so you won't affect torches, candles, etc. It is, however, perfect for turning off all the lights in Novigrad at once :D which is why I left it as a console command for anyone who wants to play around. Geralt won't snap his fingers when you do this, though.

Regarding the parameters:
b - true/false (true- ignite, false- extinguish)
radius - float value (number), if not entered will use default of 15 (you can use 1000 or something for Novigrad)
dontfade - true/false (enter true if you don't want the lights to fade, will be false by default)

Installation:
Drop the "Mods" and "bin" folders into your main Witcher 3 directory, then run Script Merger. Upon launching the game, go into settings and configure the mod. Or don't, it'll do it for you.
This is a pretty lightweight mod, and it doesn't edit the vanilla scripts much. I made it so that it should automatically merge with Ghost Mode (and hopefully W3EE)

My other mods:
Accessory Slot Mod
Wearable Pocket Items
Auto Hide Weapons for Cloaks
E3 Combat Cam Shake
Natural Cat Vision
Show Kill XP
Save Equipment Presets
Firearms Belt Holster 2.0 - Addon for Roenaxx's Firearms
Intuitive Fast Travel (Seamless Signpost Interaction)
Level Up Popup Fix