ContourPlot3D[y^2*z-x^2==0,{x,-10,10},{y,-10,10}, {z,-10,10}]

ContourPlot3D[x*y==0,{x,-10,10},{y,-10,10}, {z,-10,10}]

ContourPlot3D[{y^2*z-x^2==0, x*y==0},{x,-10,10},{y,-10,10}, {z,-10,10}]