tetrahedron
I cannot think of any 2-d shape. The 3-d shape with four faces is a tetrahedron.
Tetra = four. It is a 3-d shape with 4 faces.
A 3-D shape with 8 faces is an octahedron.
A square pyramid.
Pyramid
All of them.
octahedron
A tetrahedron is the smallest possible polyhedron: a closed 3-d shape with polygonal faces. It has 4 triangular faces, 4 vertices and 6 edges. It is also known as a triangle-based pyramid.
An octahedron is a closed 3-d shape with 8 polygonal faces. There are 257 topologically different convex octahedra. In most cases there will be no parallel faces but there can be four pairs of parallel faces.
A triangular based pyramid has 4 faces, 6 edges and 4 vertices
-9
A cone