In two dimensions, all sorts of triangles. In 3 or more dimensions there is no specific name for shapes with three vertices.
2-dimensional shapes, with three straight sides have three vertices.
A rhombus is a two dimensional figure while the concept of {faces, vertices and edges} is relevant to 3-dimensional shapes.
Most 2 dimensional shapes (all polygons) have 3 or more vertices. Most 3-dimensional shapes (polyhedra) have 4 or more vertices.
There are many shapes that have fewer than 3 vertices like the circle, hyperbola, semi circle, and many others. However if you are only talking about polygons then there is no actual shape with fewer than 3 vertices that you can find in a real life situation but they do have names for these shapes. A 2-sided polygon is known as a digon. A 1-sided polygon is known as a monogon. These shapes only exist in theory however and not in real life.
In 3 dimensions, a sphere, an ellipsoid, or a blob.
cube 8
Yes. A sphere, an ellipsoid, a toroid.
In 2 dimensions, a quadrilateral. In 3 dimensions, a tetrahedron.
A triangle is the only polygon with 3 corners (vertices). There is no polyhedron with 3 corners.
3 vertices
A triangle has three sides and three vertices.