While the wiki is being created, this is a complete list of all 71 Regions Unexplored biomes as of v0.5.5. Each listing contains the biome name, id, description, and two images. One image is taken without shaders (Vanilla), and the other with Complementary Unbound shaders with default configuration.
As a note, I do not consider myself an amazing photographer. Enjoy the screenshots there are! I hope this list and descriptions are of help to you.
Overworld