The Kana Tank is named as the best brush for woodstains & varnishes. Well worth checking these out if you have an upcoming project.
Best Brushes For Staining Wood
The Best Paintbrush for Oil-Based Gloss - Decorator's forum UK
Caparol PU Satin Review - Water-based Satinwood - Decorator's forum UK
Minwax PolyShades Wood Stain + Polyurethane Finish – Quart, Bombay
Best Place to Buy Paintbrushes - Decorator's forum UK
Varnish Archives - Decorator's forum UK
How to Apply a Varnish to an Acrylic Painting
Harris 102021060 Seriously Good Woodwork Stain & Varnish Paint
General Finishes Water Based Wood Stain Pints and Quarts FREE
Harris Seriously Good Woodwork Stain & Varnish 1in Paint Brush