2D Something like fog of war - things are invisible out of light stripe

there are several 2d mask plugins that you can take a look in the asset store, i think you may need those.

To manage all light source, the easiest way is to render them all in a rendertexutre but it will be too big, unless your scene is very small. i think for better performance, you need to write your own component and shader, so that when you get under a light source, you only use that light source to do masking