Some brushes I use:
For the initial lay in I use hog flats or filberts. I've used cheap brandless ones for a long time, but lately I've switched to Rembrandt.
For most details I use round ox hair brushes (Vincent). For the smallest details I sometimes use Da Vinci ox hair flats with shorter hair than the Vincent brushes.
In addition I have a couple of sable liner brushes for long strokes.
For softening strokes of paint, I use empty Langnickel 5590 brushes and large plain house painter's brushes (ie. Veba 8.)