So let's say your character gets hit by charm person. It has the enchantment (charm) and mind effecting subtypes.
You are playing a custom race made with the race builder rules in the SRD with 3 different racials - Stubborn, Resistant, and Dual-Minded:
Stubborn (2 RP)
Benefit: Members of this race gain a +2 racial bonus on Will saving throws to resist spells and spell-like abilities of the enchantment (charm) and enchantment (compulsion) subschools. In addition, if a member of this race fails such a save, it receives another save 1 round later to prematurely end the effect (assuming the spell or spell-like ability has a duration greater than 1 round). This second save is made at the same DC as the first. If the member of the race has a similar ability from another source (such as a rogue’s slippery mind class feature), it can only use one of these abilities per round, but can try the other on the second round if the first reroll ability fails.
Resistant (2 RP)
Benefit: Members of this race gain a +2 racial bonus on saving throws against mind-affecting effects and poison.
Dual-Minded (1 RP)
Prerequisites: Humanoid with two subtypes or race with half-construct or half-undead subtype.
Benefit: Members of this race gain a +2 bonus on all Will saving throws.
None of them state whether they do or do not stack.
Would all 3 of those apply?
I'm aware that the same effect from multiple sources typically does not stack; these all do the same thing but the conditions vary, so I wanted to check.