This mod will aid in your overall building within Minecraft. It has wands capable of duplicating your last placed blocks and even repairing portions of your architecture. All you need is the wand and enough of the items in your inventory. The swapping wand allows you to shift+right-click any block and then you can replace a designated series of blocks with another right-click.
The building wand will add the same block adjacent to where you’re placing a new block. This is particularly helpful if you happen to have some gaps in your construction and instead of finding that block in your inventory, you can just use this wand to fill them in. It’s also helpful for duplicating a series of the same block.
And with the same wand if you shift+right-click you’ll undo up to your last two block placements!
And on the same subject as moving objects, you can use the capturing wand to move any mob wherever you like. Especially helpful with wayward animals in the wrong places but can also be used on common enemies like creepers and zombies.