There are plenty of 2d raster graphic applications that offers those kind of thing, but for workflow purpose on Krita and GIMP, it would be interesting to see g’mic offer some new procedural textures.
How about Plasma? http://gmic.eu/tutorial/_plasma.shtml. There are probably other filters / commands if you search http://gmic.eu/reference.shtml and the GIMP plugin.
Plasma is fine for cloud texture in GIMP and Krita. I was thinking G’MIC should have more of those thing on the line of these things here - Fluid Texture attributes | Maya 2016 | Autodesk Knowledge Network
From the link
Perlin Noise - The standard 3D noise used in the solidFractal texture.
Billow - Has a puffy, cloud-like effect. Billow is computationally intensive and therefore slow.
Volume Wave - A sum of 3D waves in space.
Wispy - A Perlin Noise that uses a second noise as a smear map. This makes the noise stretch out in places, creating a streaky, wispy effect.
And then, with Krita, there were plans to make Generator Layer which is essentially layers that is kind like a non-destructive version of 2D procedural texture generation as in you can change variables at any time, but no one has gotten to the task of converting Shiva code into C++, so Krita isn’t going to get it in a long time. This would allow some users to use Krita as a filter forge alternative as clone layers enables something like node editing even if it not exactly node editing.
Texture generation could be lots of fun. I remember playing with that a long time ago when CorelDraw used to be good. I think Inkscape has some capabilities in this area…
Inkscape can’t be used to edit raster graphics though. I would love a FOSS version of FilterForge even though I own a copy of it.
I still use it to generate and export PNG textures. Clumsy, yes.