my favourite effect is this though. while level objects that occlude units are faded out to display the foundation/scaffolding instead, another way to know where units are is by their selection boxes. those same boxes will be occluded by the units, but not by the environment details. if you look at the foremost tank there, you can see this effect in its most pronounced state
this is just done with render queue bullshit but it also allows me to make use of some more subtle effects. for instance, because the boxes are always drawn over the terrain, I actually put them about 0.25m below the units they're assigned to, which gives them a subtle parallax that I just think looks neat