Here's one more tool for 3D painting.
Tools developer Rod Zilla has recently released a new update to his node-based material authoring software Material Maker adding a new layer-based 3D texture painting toolkit.
The latest version allows you to use Material Maker for painting PBR materials for 3D models and managing albedo, roughness, metallic, emission, and depth channels which can be painted at the same time. The normal map is generated from the depth channel.
The tool supports 3D materials, tri-planar mapping, following the cursor's movement, and more. The developer plans to add more features and brushes in the future. There's also basic support for layers.
The latest version, Material Maker 0.95, is now available for Windows and Linux under an MIT license. It can be used as an add-on for Godot and as a standalone tool.