this is a texture pack called BasicCraft. its basically a non detailed version of minecraft's original texture.
Why do I have a feeling I've seen this before?
Oh, because I have!
If you're thinking of making a non detailed version of MC's original textures, then also keep in mind that that is one of the reasons there's so much hate towards the simple packs.
There are so many "simple versions of minecraft textures" it's just scary.