I've tried some plugins and scripts for light rays, but can not find what I want. The closest thing I've found is in G'MIC, but the filter has a problem, there is only a point source of light.
For example I want starting from an image like this:

Generating light beams. I have used the filter "wind" in G'MIC and then applied blur:

Is ok but I wish I could choose that the beams are conical rather than cylindrical:


I must say I've tried applying the filter "Wind" with different angles and then combining the layers. But where the rays overlap the result is not good.
It would be nice to have a plugin that starting from an image with a certain amount of white dots or circles, to make light ray effects being able to choose length, angle, single light source or light source at each white point or circle. Cylindrical or conical beams, etc.

Try this, generate your light rays the top width, transform the bottom width.

@Odinbc, I do not know if I understand you. You mean transform light beams one by one?
I intend to apply the effect to a grid with hundreds of holes

YAFU, won't another GMIC Filter do the job? I mean Light Rays in Lights&Shadows.



There is also a PS plugin that works in GIMP via pspi - L'amico Perry's "Luce". You might wanna check it out too.

Done some spot light rays, looking at the old xcf, I just draw a triangular selection filled with white then blurred by about 50, finally added a layer mask with white to grey linear gradient running in the direction of the beam then lowered the opacity of the layer to 75%.

@K1TesseraEna
Yes, as I said earlier in G'MIC filter light comes from one source. There each light beam coming from a single point. Besides you have less intensity in the beams away from the light source.

In fact I'm trying to make a wallpaper:


I managed to get something like what I wanted to apply the filter "wind" in both angles and combining the layers (as already said before). But as you can see inside the red selection (as in the center of each hole), rays in the junction have different directions and is not credible.
I do not want to apply much blur because I have the intention that some rays are visible.

About PS plugin, I'm in GNU/Linux

@he4rty, I'm not good with layer masks
Then I will try to do what you say.