Glow/Transparency effect for meshes (Blender)

In many different games, I have seen a glow (rarely transparency) effect for certain meshes (a gradient, usually based in the center), and I would like to ask how it could be replicated. I have found nothing relating to this so far. 1st image: Glow+Transparency, 2nd and 3rd: Glow
image
image
(faint)


Thanks for any help

mmm thoes are like… 3 different images…

The first one looks like a neon mesh with a texture on it

the second one look like it was vertex painted according to this post

and the last one looks like a flashlight was shined on it, or a really dark vignette effect.