fill-stick-tool

This plugin ads a fill tool optimized for filling special strucktures like mazes .
Simply right-klick on a Block (with the tool) and the air blocks ,ontop of every Block on the y-Level of the klicked block, gets replaced By the block in your Hodbarslot 0.
This plugin lets you change the radius ,as well as some other conditions of the fill.
It gives you also the abilyti to save your chois of options and load them from an item .
And even if you make an mistake filling somthing wrong you can undo the (direct) damage (mostly) by using '/undo-fill' (for more details see in the dockumentation).