I am looking for ways for a character to become immune to the (5%) chance of automatically failing a saving throw because of a natural one on the d20 roll.
Aside from the Knight class at level 17
You no longer automatically fail a saving throw on a roll of 1" (PHB2 page 28)
and the feat Steadfast Determination
You do not automatically fail Fortitude saves on a roll of natural 1 (PHB2 page 83)
I could not find further sources or effects.
I vaguely remember the claim of someone writing a post or article about the Knight class, claiming one can get immune to natural ones on saving throws at level 1 - so I suspect there might be items with that effect.
Sadly, I find it quite hard to find relevant information via Google based on the specific meaning of the generic terms used for the issue.
Question: are there further sources to remove the "natural 1 = automatically failed saving throw regardless of the save bonus" rule?