I’ve gotten pretty far using FOSS tools when it comes to making games, but I would like something like Substance Painter so I can fully dabble into 3D.
Nothing AAA quality or very professional, I just want something that works good enough for my indie games lol.
Blender for the texture painting
Material Maker for turning those textures into game engine ready materials. It's also capable generating textures using noise and other patterns. Examples
Common Blender W
Oh cool, i didn't know Material maker does displacement.
Armorpaint might be what you are looking for. Blender texture painting is nice, but Armorpaint is much closer to the substance painter experience.
Edit: For example, with Blender texture painting, unless you're familiar with nodes, you would usually only set up one texture at a time.
Armorpaint also uses nodes, but it also uses a layer system just like substance painter. You can then modify the texture using nodes if you want to.