I'll let you know what I think of the ones I own
109 - I use this everyday for my studio fix fluid foundation, it gives a flawless application, I couldn't live without it. My mom loves it for blush also, its multi purpose.
116 - I don't own this.
129 - Great blush brush, very popular.
182 - Have it, need it, love it, cherish it. Great buffing brush, perfect for powder applications and buffing. I would highly suggest it.
187 - Another fantastic multi purpose brush. For a long time I used this brush for Studio Fix Fluid, its also perfect for powders and blushes, etc.
194 - I have this, and in all honesty, for concealer, I like thhe 252 brush better (strange, I know, but I swear by the 252 for under eye and spot concealer, I like how the bristles softly positions the product on your face, the 194 can be rubbery almost imho.
217 - My second ever mac brush, great for crease work, I love it.
219 - So multi purpose. I use it for highlighting the inside of my eyes close to my tearducts, also to smudge out eyeliner and other lines, and to place product on the lower lash line.
224 - Fantastic blending brush.
239 - I use this every single day, I'm thinking about buying a second one. SO useful, if I could only own ONE mac brush, this would be it.
266 - I prefer the 263 or the 209 if you're looking for an angle brush. The 263 gives the thinnest line between those two angle brushes. I like the hairs in the 209, I use it for filling in my eyebrows.