How do I render line graphics/grids in 3D games?

I’m talking about things like glowing grids for stuff like level editors. Not a 3D grid mind you (though knowing how to make those as well would also be cool) but grid/line graphics that appear in 3D. Actually, knowing how to implement grids that your mouse can snap unto in general would be cool.

You could do it all manually with line renderers. You could do it with an asset like Terrain Grid System. Maybe you could use a Tilemap.