GIMP might be the little brother of Photoshop but it is a really powerful program and the truth is that many top web designers design solely with GIMP. There might be fewer resources for GIMP than there are for Photoshop but still there are enough resources you can find online. Almost all of these resources are free, which makes it even better. For instance, have a look at this list of more than 40 fantastic GIMP brushes:
Hearts and Flowers
A nice set of 9 brushes.
Some more heart brushes in different shapes.
This first pack of heart brushes contains 24 brushes, like heart clusters, hearts with arrows, broken hearts, etc.
The second part comes with 26 more brushes, as cool as the ones in the first pack.
A set of 12 flower brushes.
6 flower you can try on the canvas before you decide whether to download them or not.
9 big brushes each of which is at lest 1300 px.
This second pack contains 6 more flower brushes.
A pack with 16 full pine branches and 33 separate parts you can combine to make a branch of your own.
Earth, Sky, and Stars
A Photoshop set of 22 brushes converted for GIMP.
A set of 22 high-resolution brushes, mainly plump cumulus clouds.
A set of stars in various shapes.
Another Photoshop convert with 22 brushes in it.
There are 20 snowflakes in this pack.
This brush pack contains 9 cute bubbles.
26 beams of light for your designs.
A pack you might know from Photoshop, now converted for use with GIMP.
Shapes, Curves, and Swirls
A pack of 11 big brushes.
Some basic shapes like squares, circles, and images that consist of them – 11 brushes altogether.
A pack of curves, curls, and loops.
Some very basic line brushes.
A pack of 27 extremely high resolution (2200 px on average) smoke and glitter brushes.
26 swirls and separate parts to combine into a swirl of your own.
Another pack with 25 more swirls.
This pack includes 2 animated brushes in different sizes.
Grunge, Crack, and Splatter
A pack of grunge brushes with various effects.
27 brushes, originally for Photoshop with different grunge/dirt effects.
A pack with some more grunge brushes.
A pack of 6 brushes 500-700 px each.
12 brushes of cracks and walls.
A pack of 23 more cracks, the majority of which are 1100+ px.
A pack of 2 animates and 10 standard size brushes.
A pack of 10 blood brushes, 1000 x 1000 px each.
This is a really huge pack, probably one of the largest out there. Kind of old, but still very useful.
A pack of 9 cute butterflies.
A set of 34 brushes – there are pairs, but also there are left/right ones, too.
A whopping 41 brush-set of cheerful doodles.
Some cute dice to use in your designs.
A pack of fingerprints you can use for dirty marks, too.
31 micro patterns, mainly lines and derivatives, that have been converted to brushes.
47 handwriting brushes with different handwriting styles.
If you know some of the brushes on this list, this is hardly an accident because the latest versions of GIMP allows the use of Photoshop brushes and if you have seen the same pack for Photoshop, chances are you can use it with GIMP, too (though sometimes not everything will work the same way it does in Photoshop and this is why it is better to get a brush somebody has already made for GIMP). Some of the brushes here have been originally created for GIMP (and later exported to Photoshop), while others were first created for Photoshop and then exported for GIMP. In any case, these brushes are a valuable addition to your arsenal, so just install them and start using them in your projects.
I am a fulltime freelancer from Sofia, Bulgaria. I have long ago discovered that freelancing is the best option for me because it allows me to grow professionally as a writer, designer, web master, etc. and doesn't confine me to a 9 to 5 schedule. Ditching my fulltime job (and I have changed so many of them) was the wisest decision I have ever made!