This is an Allosaurus Skeleton by Robert J. Lang which was inspired by the brilliant Tyrannosaurus Rex of the late Issei Yoshino. You can find more of his works here.
This is a cobra model by David Derudas. You can find more of his works here.
A hermit crab by Brian Chan. He has a lot of other great origamis artwork. You can find more of his works here.
This is a multipiece dragon design by Joseph Wu, inspired by the feline dragons which was introduced in the 3rd edition of Dungeons and Dragons. You can find more of his works here.
A great origami model of Icarius by Hojyo Takashi. You can find more of his works here.
Starcraft fans will be able to recognise this unit as the mutalisk of the Zerg race. Another great origami by Jason Ku. You can find more of his works here.
This one is my favourite. Awesome origami Shadow Ninja by talented Hoang Trung Thanh. You can see more of his works here.
God of Thunder, Raijin by Hojyo Takashi. His origami works are one of the best you can find online. You can see more of his works here.
Awesome model of a reaper(shinjigami) by Hoang Trung Thanh. You can find more of his works here.
Final Fantasy VII Sephiroth in Origami. Great work by Brian Chan. You can find more of his works here.