Following is a list of some of my heavily used brushes that have maintained their shapes through rigorous painting and cleaning processes.
1. Princeton Ashley, Brushes for Acrylic and Oil Series 5200, Interlocked Chungking Bristle, Flat Size 2 (approx. ¼ inch).
2. Princeton Dakota, Series 6300, Synthetic Hog Bristle All Purpose Paint Brush, Professional 4-Piece Set (various types and sizes).
3. Princeton Imperial, Synthetic Mongoose Brush for Oil & Acrylic, Series 6600 Angle Bright, Size 6 (approx. ¼ inch)
4. Silver Brush Limited 1001 Grand Prix Flat Brush for Oil Paintings, Size 6, Long Handle (approx. 1/2 inch).
5. Silver Brush Limited 1903 Bristlon Bright Brush for Acrylic and Oil Paintings, Size 6, Long Handle (approx. 1/2 inch).
6. Robert Simmons Signet Brushes Size 4 Bright 40B (approx. 3/8 inch—plastic handle is not damaged by water).
7. Escoda Modernista Series 4075 Long Handle Artist Oil & Acrylic Brush, Size 2, Round (approx. 1/8 inch).
8. I recently started using Rosemary Co. and Sennelier brushes so I will not rate them, but they are popular among professional artists.
9. Note that I use pallet knives and cotton ear swabs (on a wooden stick) like paint brushes. They facilitate painting and cleanup of my images.
Normally, I use 20 to 30 brushes during a painting session. I routinely clean them with baby oil, then dishwashing solution for maybe 10 painting sessions before I deep clean them with Turpenoid Natural. See my YouTube Video on that subject: https://youtu.be/LT5EWyQlVpM