From the Class Guide, Steadfast Personality allows you to add your CHA to Will saves instead of WIS. Are there other feats that let you add your CHA to your Fortitude or Reflex saves too?
First, I highly recommend this document. It is not really up-to-date but it is still useful.
As a feat, there is only Divine Protection lets you add your Charisma to one saving throw a day, by an immediate action. It used to be way more powerful but the nerf hammer stroke hard.
But there is also this trait: Irrepressible, (that you can obtain through the Additional Traits feat), which lets you use your Charisma instead of Wisdom for saving throws against charm or compulsion.