EcoTools Foundation Brush - obviously for foundation but I also use this to dab on my under eye concealer
Bamboo Angled Eyeliner Brush - I use this when I use my gel liners. Works fab and you get a nice steady line and easy to angle with. Also sometimes I use this to dip into a black shadow and lightly tap onto my lower lash line for a smoky look.
EcoTools Kabuki Brush - I finish off my makeup with this dipped into a little bit of loose powder
Stila Double Sided Eyeshadow/liner brush - I love shadow brushes. The amount of makeup you can do with eyeshadow brushes is crazy. But when I'm lazy and don't want to try anything new with my eyes I use this brush. The bigger side is used for an all over neutral color on my lid and the thinner side I use with a dark color to fill in my crease.
MAC 116 Blush Brush - blush brushes are so important in how it applies onto your cheek. You don't want it to big or else you'll just have bright pink cheeks so having it a bit smaller gives you a more concentrated area and then being able to have control over how much area it goes over.
If you are looking for a good set to start with, I recommend this for your face basics. You can use the big fluffy brushes for your powder and overall setting of your makeup, and it also comes with a concealer brush and a eye shading brush which is awesome for blending your shadows.
I recommend EcoTools because the price is great and I haven't had trouble with their brushes losing bristles, getting stuck in my make up or finding random bristles on my face after I used it which has happened to me with other cheaper brands.
If you are looking to invest in brushes, Bobbi Brown has a set of Basic Brushes. It comes with six brushes: Concealer, Foundation, Face Blender, Eyeshadow, Eyeliner and Eyebrow, which gives you everything you need for a great basic set. I actually started out with Bobbi Brown brushes but over the years had to get rid of a few and have since replaced them but I have always liked her brushes.
If you want something in an in between price point and a little more than just basic brushes, I have this Sephora set and highly recommend it. The only thing is the bristles are a bit harder than I prefer and I don't love the powder brush (it's a bit thick and takes a bit more powder than I like) however, it's a great price for the set and the brushes are good quality.