It's hard to tell from the picture but I'll take a stab at it (from left to right):
1 - Lip Brush
2 - Fan Brush = MAC 207 used for applying bronzers, powders, blushes, etc.
3 - Spongetip Applicator = MAC 202 used for packing on eyeshadow
4 - Lash Groomer = MAC 204 used for defining eyelashes
5 - Brow Groomer = MAC 206 used to shape and define brows
6 - Eye Liner = MAC 209 used for applying a very fine line
7 - Eye Liner = MAC 211 used for applying a fine line
8 - Crease Brush = MAC 219 used for applying color in the crease as well as softening lashline
9 - Concealer or lip brushes
10 - Concealer or lip brushes
11 - Small Eyeshadow Shader = MAC 228 used to apply small amounts of powder or cream products for precise and intense application
12 - Eyeshadow Brush = MAC 213 used to apply a wash of eyeshadow
13 - Eyeshadow Shader = MAC 242 used to apply powder or cream products for precise and intense application
14 - Eyeshadow Shader = MAC 249 used to apply or blend color
15 - Eyeshadow Shader = MAC 239 used to pack on color, apply wash of color and blend
16 - Eyeshadow/Crease Brush = Bare Escentuals Heavenly Eye Brush used to stipple on eyeshadow to lid or crease
17 - Agled Shader Brush = MAC 275 used to apply wash of color or blend eyeshadows
18 - Blush Brush = MAC 116
19 - Angled Contour Brush = MAC 168 used to apply brush to apples or hollows of cheeks
20 - Powder Brush = MAC 129 used to apply powder foundation or loose powder to face
