Aside from the cloak or vest +5, there's the luckstone and pale green ioun stone. You can use stat boosters to shore up a glaring weak save. Iron Will is often useful for fighter or rogue types to help against domination. Mass Conviction is insane.
Enkidu means Protection from Spells, not Protection from Evil. Sure, it's a resistance bonus, but it's like +8. That means it's a nice +3.
Spells like Mind Blank, Deathward and Energy Immunity can also diminish the need for saves by replacing them with immunities. A Rod of Absorbtion or Ring of Spell Turning can also negate many save based attacks.
Strategic multiclassing can also pump saves up quickly, either via the +2 jump on good base saves, or by class abilities. Rage boosts Fort and Will saves and the bonuses increase at higher barbarian levels - in fact, with Indomitable Will, the Will save goes up alot! Divine Grace with a pumped Cha can make success virtually guaranteed.