The Kana Tank is named as the best brush for woodstains & varnishes. Well worth checking these out if you have an upcoming project.
A brush for every type of painter – The Decorator
All you need to know about varnishing paintings
brush Archives - Decorator's forum UK
Harris 102021060 Seriously Good Woodwork Stain & Varnish Paint
Osmo Oil Review and product guide - Decorator's forum UK
How to Apply Interior Wood Stain
brush Archives - Decorator's forum UK
Axus Decor Wood Finishing & Varnish Brush (Lime Color) - 1.5/38mm
How to clean, polish and repair antique wood - Homes and Antiques
Put Down That Paint Brush! And Other Tips from An MCM Furniture
UK Are Lagging Behind with Paint Brushes - Decorator's forum UK
Harris Seriously Good Woodwork Stain & Varnish 1in Paint Brush
The Best Paintbrush on the Market - Decorator's forum UK