There is no such thing as a 3d triangle. A 3d shape which has only equilateral triangular faces can be a tetrahedron which has 4 faces or an icosahedron which has 20.
tetrahedron (triangle-based pyramid)
Only one; a triangle is a 2D shape, not a 3D shape. Usually only 3D (or more) shapes are considered to have 'faces'.
An octahedron is a 3d shape that has eight faces. An octahedron is made from equilateral triangles, with four points meeting in one spot called a vertex.
3d shapes with six faces are called hexahedra.
There are infinitely many shapes that do.
Hexagonal prism has percandicular faces
a triangular prism