Sigma F80 Flat Kabuki - I apply my foundation with this every single day. It's perfect for buffing the foundation into my skin to get a flawless finish. It doesn't make me feel as though I'm just rubbing product around my face without getting any results, which has happened many times before.
E30 Pencil - I searched far and wide for a true pencil brush. I had a hard time getting a smoky under-eye area without the classic "I was punched" look. The bristles are loose enough for blending but stiff enough to give you ultimate control of where the product is being applied. It's also perfect for smudging eyeliner or getting a perfectly defined cut crease.
E40 Tapered Blending - The best blending brush under the sun. I feel like I have control over color in my crease with this, but it buffs it out beautifully. Blending never used to be my forte as I could never get it exactly right. I always use this to apply my crease color or to blend everything together in the outer corner. It just makes every look feel more polished.
E25 Blending - While this is also considered a blending brush, it's a multipurpose tool for me. I use it to apply crease color and blend it a bit so it doesn't look too rough, but not for an overall blended effect as I would with the E40. I use this to pat color on my lid as well. It really helps to pack on the color and move it around the lid without flinging product and creating fallout.
F55 Small Duo Fibre - While also a multipurpose brush for me, I stick to using this on the cheeks. The duo fibre brush is perfect for applying cream blushes and highlighters. It gives cream/liquid products an airbrushed finish. I occasionally use this to apply extremely pigmented powder blushes as well - they don't pick up the amount of product that regular blush brushes tend to, sparing you the clown cheeks.