I'm going to second Coastal Scents - they have a super tiny eyeliner brush that I love because I feel like it gives me a lot of control for both eyeliner and doing my eyebrows. It's called the "Classic Angled Liner Small Natural" - I haven't been able to any this small from other brands (yet).
I've heard good things about the different liner brushes from both Morphe Brushes and Coastal Scents. They seem to be quite affordable as well.
I'm going to second Coastal Scents - they have a super tiny eyeliner brush that I love because I feel like it gives me a lot of control for both eyeliner and doing my eyebrows. It's called the "Classic Angled Liner Small Natural" - I haven't been able to any this small from other brands (yet).