I found on Deviantart a amazing collection of dynamic presets , brushes palette called GimpBrushBox V2.1
It remind me a bit Ramon GPS , also for completeness.
And the same author offer also other resources , all organized in packs here the brushes (most for gimp, some for Krita )
And there is even more I am just found a pack of palettes and gradients
http://grindgod.deviantart.com/art/Gimp ... -403630033 that seems really worth a try
and here pattern
http://grindgod.deviantart.com/gallery/43039580and even more on his blog
http://vascobasque.wordpress.com/