Minecraft's vanilla textures are 16x16. Now imagine downscaling this 16 bit resolution into 8 bit. That's what the 8BitCraft 2 texture pack offers you. All of the textures in this pack are based off vanilla textures. So, this pack lowers your texture resolution in half without straying away from the vanilla game. This pack also has numerous other features like connected glass, block transitions, plant variations, glowing stuff, 3D models, etc. You will need Optifine to enable some of these features, so make to have it installed.
Download links and installation instructions are given below.
How to install
1) Download the texture and Optifine
2) Put in .minecraft/resourcepacks folder
3) Put optifine in .minecraft/mods folder