Allows GIMP to read, edit, and save '.vtf' files, using a layer mask as the alpha channel, or a different layer entirely.
A big set of filters, which function like the 'filter gallery' from Photoshop, with some extra stuff. Also allows you to make your own filters, read here how.
Allows for normalmap creation, also allows you to look at a 3D object for preview.
Allows GIMP to read, edit, and save '.dds' files, using layers as mipmaps.
Allows you to make use of layer styles just like in Photoshop; not all of these are in G'Mic, and even if they were, this is much more accesible. Though it doesn't really function like the way photoshop does it, it can be put in new layers so not all is lost when you mess up.
Tutorial for batch converting TGA files to JPG, which can also be used to convert anything GIMP can open to anything GIMP can export.
Video tutorial for making a signature.
Explains how the path tool can be used to modify a selection.
Simple, but effective, way of making gradient text.
Two easy to follow tutorials for making a signature
A somewhat overcomplicated way of making a transparent spray.
Easier, yet outdated, way of making a transparent spray.
Simple brushed metal tutorial, which I guess doesn't tile, but will probably work well enough for texturing purposes.
Video tutorial on how to make a buy menu image, though I should remark you get better results if you make the hand invisible by putting '$no_draw 1' in a 'hands.vmt', and use the v_model anyway. Also note that the GIMP has a function that can create an image by selecting a window, or from clipboard.
Outdated, but functional, tutorial on making a decal.
Tutorial on making an animated '.gif', can also be used to make a '.vtf' with frames.
Interesting tutorial on making an animated special effect.
Real fake HDR screenshots.
Simple tutorial on making very simple reskins, this is for newbies only and the results should never ever be submitted; though perhaps in combination with some selection trickery, it could at least be decent.
Selfillumination.
Proper JPG export
Metric fuckton of brushes exclusively for GIMP.
droz928 brush setA seriously unfunny quantity of brushes for GIMP.
DeviantArt's GIMP brush collectionGo nuts.