These fellas will be heading through your letterboxes soon, celebrating 50 years of the WWF - the World Wide Fund for Nature.
The WWF works on lots of environmental projects right around the world, including helping African elephants like this one.
The Iberian lynx is the world's most endangered cat. Loss of its habitat has meant numbers of the cat are falling.
This red panda might not look like a giant panda, nor is he as big, but like the giant panda deforestation means there could be fewer places for the animal to live.
The WWF say the stamps raise awareness of problems like deforestation and climate change.
The elephant and tiger stamps are intelligent stamps - so smartphones can scan them and view more info about the endangered species.
There are ten 1st class stamps in all featuring different endangered species which the WWF have worked to help.
There's also a special set of four stamps with pics of animals from the Amazon rainforest.