BSP Based Square Terrain - terrain in UndEd1-style, sides made of 4-vertex polys instead of triangles. Has randomization tool for top vertices.
Randomized Sphere - sphere build from octahedron with specified extrapolation level and randomization of base vertices. Can be used to create stones, etc.
Old Staircase - staircase with separated steps not connected with each other. Rotation of steps can be randomized.