Scarab beetle by Fumiaki Kawahata

 From Fumiaki Kawahata's Origami Beetles of the World.

Maple Leaf 2 by Takuji Sugimura

 From Takuji Sugimura's Origami Greetings.

Stegosaurus by Yoshihide Momotani

 One square of gold foil-backed paper. From Yoshihide Momotani's Origami Dinotopia.

Regular tetrahedron skeleton by Tomoko Fuse

 Made with 6 squares. From Tomoko Fuse's Three Dimensional Karakuri (Origami Land). (Not sure of the translation; another source calls it "Three Dimensional Trick-Unit Origami". I thought "karakuri" were Japanese automata.)

Cruising Boat by Yoshihide Momotani

 Made from a 2 x 1 sheet of paper. From Yoshihide Momotani's Origami Ships.

Modern Cube by Kunihiko Kasahara

 Made with two squares (one a little smaller than the other). From Kunihiko Kasahara's Origami Discovery 2: World of the Cube.

Sunflower by Tomoko Tanaka(?)

From Tomoko Tanaka's Origami Shikishi Hundred Flowers ["shikishi" = colored paper?]

Center is made from a separate square of paper.

 I'm unclear about the authorship of this model and book. I think it's either jointly authored by Tomoko Tanaka and Makoto Yamaguchi, or else Yamaguchi was the editor. (Yamaguchi owns "Gallery Origami House," the publisher.)