[solve]How do you make this texture?

[amazingJukes]

You can tile-paint whispy waves in Krita with particle brush:

And there are filters like that for Filter Forge:
Whisp Filter

And yeah, like jqarlsson1h said, you can always tile any image you want manually in Photoshop. Krita is great for seamless painting too, tho not that convenient imo.