Simplify is a resource pack for Minecraft containing textures and other graphical resources (a texture pack). It is a “simple” pack (thus the name), featuring basic recurring shapes and color palettes, and shaded edges to help tell adjacent blocks apart. While textures may appear similar to those in other texture packs, they were created by Fenhl, using only the default textures as a starting point.
This texture pack should update whenever Minecraft updates, so if it lacks textures from the latest Minecraft release, feel free to submit an issue.
There are some screenshots.
If you download Simplify as a zip, you can put the file in the resource packs folder and it will work.
You can also clone the repository.