2D Blocks GUI is a lightweight Resource Pack with builders in mind.
The Resource Pack simply changes the look of BLOCKS in the inventory screen, including the creative menu. This allows builders to easily find blocks and create colour palettes with them. Resource pack makers may also find this useful to easily see textures.
This pack works for 1.9 and 1.10, with future versions usually being supported automatically due to the nature of this pack. This Resource Pack can be combined with any other Resource Pack and the textures of those RPs will be displayed as 2D as well!
See this video for more information: