If I am buffing in a powder (like MSF natural) I used the Mac 183 brush. This is great for bare minerals as well, or even if you are buffing in a liquid foundation.
For blush I use the Nars blush brush, I used this in a circular motion when putting blush along my cheekbone.
For bronzer - Nars Bronzing Brush - I LOVE this one. its super dense and amazing for applying bronzer!
Nars Concealer brush - I honestly use my fingers most of the time for concealer, but if i am taking the time to do a really good job, this would be the brush I reach for.
The basic brush that I use the most
Mac 217, I use this for everything. Laying down shadow on the lid, crease work, you name it and this brush can do it.
mac 224 Brush - for larger blending areas, i might used i after using the 217
Nars Eye Contour Brush- this i used for smaller crease work, like if i am blending in a darker color in the outer V
Mac 219 Pencil Brush - This is very similar to the brush above, but i use this for highlighting on the brow and in the inner corners
Nars Smudge Brush- This is such an awesome brush! its perfect for when you are doing a smokey eye and want to smudge shadow as a liner, or ever to smudge your eyeliner you have already put on
Nars Push Eyeliner Brush - I use this everyday. I prefer to use powder as eyeliner, so this is essential. this is the best thin eyeliner brush I have ever tried, and i have tried a few. A lot of them have frayed over time, so they loose the sharp line. This one I have had FOREVER and its still in perfect shape. you can use it dry or if you want the thinnest line ever (the kind that you can barely see and looks like your lashes but better) this is for you!
Mac 266 Brow brush - one I don't use a ton, because i don't fill in my brows all that much, but is great when I do use it