Rerolls

[Minosis]

There is now the mantle of second chances, DMGII for 6000 that provides 1 reroll a day.

 

[kenobi65]

In Star Wars d20, the Scoundrel class has the "Lucky" class ability, which works pretty much exactly like the Luck domain ability (except that, at higher levels, the Scoundrel can use it multiple times per day). Then again, that's not D&D, either.

 

[silentspace]

Swashbucklers from Complete Warrior, and that pirate PrC from Complete Adventurer also have it.

 

[seans23]

Banded Mail of Luck allows you to force an attacker to re-roll an attack roll, once a week.


http://d20srd.org/srd/magicItems/magicArmor.htm#bandedMailofLuck


Complete Divine has the Resurgence spell, which allows the creature touched a chance to re-roll a failed saving throw against an ongoing spell. It doesn't apply to ability or hp damage.