Okay, this one's a bit unusual.
Long story short, .werkkzeug3 TE is a free procedural texture editor. There's no use in it being procedural, since you'll need to export the images to .BMP and such (the library that allows loading of it's internal format costs 16000 euros, I think...), but still, it's free, it has unusual interface some people might like, and it comes with a bunch of very impressive presets to get you started.
Basically, it's a texture-oriented fragment of a full .werkkzeug3, that is sadly not available to the public. .werkkzeug3 was used to create the famous .kkrieger
You'll need to fill a form to download .werkkzeug3 TE, but there's no validation involved (not even a confirmation email, IIRC), so you can enter some rubbish if you don't want to give them your personal information for some reason.