Here is my entry

First photo : A Thanksgiving cactus- it has a pointed teeth and also has a claw like point along the edge of each of the flat stem

Second photo : A fairy castle cactus - some how having the look of a small version of a castle, with it dark green colour

Third photo : A Dragon fruit cactus - having a long climbing green stems

Fourth photo : A zig zag cactus - shows the characteristics of a zig zag stem