For the Highlight

I bought the Ecotools Bamboo 6 Piece Eye Brush Set on sale a few months ago from Priceline for about $16. At the time, I was unaware of iHerb, where you can purchase it for $7.22 (you can probably get it for even cheaper on eBay). The set consists of 5 brushes, with the 6th item being a hemp and cotton case with a mirror that I chucked in my bottom drawer and never looked at again. There's a Large Eye Brush, Angled Crease Brush, Petite Eye Shading Brush, Highlighting Brush and Smudge Brush. Like most Ecotools brushes, they're pleasingly soft, though some are firmer than others. I've ended up not using these brushes to apply my eyeshadow (I'm sticking with cheap, dual-ended Sportsgirl ones to do that), but I do use two of them all the time, one for blending and the other for slightly smudging out my lower lashline.

l-r: Highlighting Brush, Large Eye Brush, Angled Crease Brush, Petite Eye Shading Brush, Smudge Brush 

Large Eye Brush ("Blend")

This brush is wide (just under 2cm across), flat and soft. It reminds me of a mini foundation brush if anything. Given its size and shape, I don't really know who would be using this for blending, or to apply a wash of eyeshadow over the lid. It seems like you'd need a lot of eye space to get use from this brush. I guess it would be better used to apply and blend concealer under the eyes, or possibly as a brow highlight.

Angled Crease Brush ("Crease")
I have a similar brush from this Ecotools Alicia Silverstone set I purchased a while ago, but slightly smaller and firmer. An issue I've found with this kind of brush is that it doesn't pack on colour well. It's large, fluffy and better for blending than applying eyeshadows. The angled shape of this brush is ideal for blending out the outer corner of the eye, especially if you've applied a darker shadow for a gradient effect.

Petite Eye Shading Brush ("Shade")
It goes from one extreme to another in this set. This brush is ridiculously tiny (7mm across). It's also really thin and flat. How it's supposed to do anything (let alone "shade") is beyond me. The only purpose I can think of is lining the lower lashline (but even then, this wouldn't be the best brush as even though it's small, it's too thin and flat), or highlighting the inner corner of the eye.

Highlighting Brush ("Highlight")
The clear standout of this set and probably the only reason I bought it as I was specifically looking for a brush like this one. Ignore the "highlight" label. This is your standard fluffy blending brush. I alternate this brush with a similar shaped but slightly softer and larger one from the Ecotools 5 Piece Brush Set. It's perfect for blending eyeshadows and softening any harsh edges.

Smudge Brush ("Smudge")
My second favourite of the set, I use this to smudge eyeliner and/or eyeshadow applied to the lower lashline so it's a little more blended out and not so harsh. The pointed shape gives precision but is also still soft. Even if the brush only has one function, it serves it perfectly.