During my last few years, I hardly picked up a conventional brush. Instead, I used Sea Sponges. They come in a variety of shapes and sizes; are easy to hold and clean. With painting areas carefully masked out, the sponge makes for a quick tool. Areas can be shaded and blended for almost magical effects.
The secret to a successful painting is the preliminary work in preparing the masking of the paper in order to preserve the white areas. However, with this carefully done, the act of painting goes along quite quickly! This is the inherent nature of transparent watercolor. It is the absolute opposite of opaque work. Must be planned in advance.
Amazon has a plethora of sponges to choose from, some natural and others artificial. The natural ones are my choice as they are more random in their shape. This randomness is what you are after for random results. Even the Artist isn't quite sure of what is about to happen! As an Amazon Associate, I earn from qualifying purchases mentioned in my various blogs. And I always recommend the best items with the best prices!