I was planning my next build and noticed that 1.7.10 lacked a way to randomly place items. That's when I decided I could probably code that up and now I'm here with Random Placer. This mod adds a singular item which allows you to place blocks randomly selected from your hotbar or your inventory.
To use this item simply have it in your hand and rightclick to place a random block that is currently present in your hotbar/inventory depending on the mode.
You can press SHIFT + Rightclick to toggle it's mode between using only your hotbar or using your whole inventory.
You can control the ratios of blocks placed by having more inventory slots be filled with the same block. An example:
You have 1 Slot with Dirt, 2 Slots with Cobblestone and 4 Slots filled with Wood. Roughly 1/7 blocks placed will be Dirt, 2/7 will be Cobblestone and 4/7 will be Wood.
If you are using the hotbar mode you can have at max a 1/8 / 7/8 placement ratio whilest in Inventory Mode you can have a 1/35 / 34/45 ratio.