mlichy on here wrote an awesome set of tools, turbotools. It has a tool in it to set pivot to center, and a tool to set pivot to center bottom. Handy when making game objects alight to a base plane.
Also, one of the Soulburn scripts has a brilliant 'pivot aligner' script that pops up a GUI that allows you to visually place the pivot in many locations, and is customisable from within the GUI. Very useful for modular assets.
The "VPP Pick Pivot Point" variation of miauu's script is also amazing. You just pick a vert and it puts the pivot to that point with no UI. It's super fast I love it.
Replies
I think I'll use this myself...you don't know what you need, until someone else needs it...