Items, Spells, or abilities that prevent a creature from being shapechanged?

So far, I've only found Moonbeam. 
Looking for items or other spells, or even abilitie(s) that can be used to prevent a creature from being forcibly shapechanged. 

Partnered Content accepted as well, except for Obojima. 

There are several enemies with "immutable form" ability which prevents them from being shapechanged.

I am looking to make a player character immutable. 

Quote from aether_tech >>

I am looking to make a player character immutable. 

Custom magic item, or just sufficient bonuses to make your save (fighter indomitable for example).