How to make an outline for a single brush stroke using Krita?
Not really a brush, but what you can do is add a layer style to a layer, by a layer and selecting layer style. Then input the following settings:
Then, set the main layer to multiply (or add a Color to Alpha filter mask), and paint with white:
(The white thing is the pop-up that you see as you hover over the layer.)
Merge into a empty clear layer after ward to fix all the effects.