This client side mod shuffles your hotbar items based on from you defined and selected "block palettes".
Its purpose is to add texture to your builds as you build them without the hassle to scroll manually through your hotbar or shift items from your inventory to your hotbar all the time.
First, open the GUI ("B" by default) and create a palette.
Each palette contains blocks added by yourself, with a weight assigned to them. The weight specifies how often a block should occur in your texturing. After defining a plaette, select a hotbar slot it should work on and select the palette itself. Close the menu, select the hotbar slot and start building.
In survival, the palette's blocks are needed in your inventory, in creative the blocks are automatically taken from the creative inventory.