Blender 3 big (Part 1) Particle Brush
I put a lot of Effort int this one so you have a good idea. Part 1 for Blender 3 since it is huge and I have another huge one in the works idea wise.
Particle brush is very simply put great for making forests, grassy plains and whatever else.
(It would work on selected mesh)
Anyways you paint it onto your scene. You have options for LOD so you can paint all you want and you do not need to worry with too much lagging. Unless you have an HP for everything then you will of course get Lag. This could work for many things, rocks, pebbles, forest, armies, etc. You would need at least a plane to work with but hide emitter as always. Images better explain the idea I think.
I probably should have added a bleed option where how much bleeding happens between colors for models. Just thought of it sadly.
Might want to put an erase tool in. With basic, and advance. Advance could use noise, and density settings for black, grey, and white. So to somewhat randomly erase.

3 Comments
OK but no particle brush before the new particle engine is working properly
* @momotron2000 * Hence why I say Blender 3 when all the huge things happen all the major big ol upgrades. Which will be whenever. Glad you like my idea though. Seems like it could be a great addition. If it is broken when it makes its appearance don't look at me. I just write things lol.
Start from the bottom. I added Imgur images on one and tried for the other but I could not delete the original image kept getting an error.