Yes, if by this question you mean to "stamp" each brush in the imagem it is possible
to do that via scriptting.
I'd recomend setting to Python for that - it is not a little bit complicated because yu willhave to deal with with things like image width, and such in order
to fit all brushes - but it should be less than 30 lines of code.
It can be done interactively from filters->Python-fu->console - from there you can make PDB calls - press the "browse" button to check what is available.
You can do, for example, just create a new image in GIMP, open up the Python console,
and paste this code into it:
img = gimp.image_list()[0]
SIZE = 30
brush_list = pdb.gimp_brushes_get_list(None)[1]
x, y = 0,0
pdb.gimp_context_set_brush_size(SIZE)
for brush in brush_list:
pdb.gimp_context_set_brush(brush)
pdb.gimp_paintbrush_default(img.layers[0], 2, [x + SIZE // 2,y + SIZE // 2])
x += SIZE
if x + SIZE >= img.width:
x = 0
y += SIZE
pdb.gimp_displays_flush()