Octomino

[1] When rotations and reflections are not considered to be distinct shapes, there are 369 different free octominoes.

When reflections are considered distinct, there are 704 one-sided octominoes.

When rotations are also considered distinct, there are 2,725 fixed octominoes.

[2][3] The figure shows all possible free octominoes, coloured according to their symmetry groups: The set of octominoes is the lowest polyomino set in which all eight possible symmetries are realized.

[4] The other 26 octominoes (including the 6 with holes) are unable to tessellate the plane.