What Resources are available to expand my critical hit multiplier?

Question

I've recently developed an interest in critical hits, and I'm looking to create the largest critical multiplier possible. Note that I'm not asking about critical threat range - I'm familiar with that - but rather the actual damage multiplier at the end. So, what resources are available to increase this multiplier? I'm already familiar with the Nightmare Blade maneuver line (a godsend for huge crits), but I'm definitely in the market for others.

Answer 1

• The Master Thrower PrC (Complete Warrior) can increase a thrown weapon's critical multiplier.
• The Deepwood Sniper PrC (Masters of the Wild, a 3.0 source) can increase the critical multiplier of a projectile weapon.
• The Dragondoom feat (Draconomicon) can increase your critical multiplier against dragons.
• The Weapon Master PrC (Sword and Fist, a 3.0 source) can increase the critical multiplier of any weapon a few times per day.

Be aware that not one of these options is one I would consider actually good considering the difficulties in obtaining them.

Answer 2

Kaorti resin gets you auto-×4 on any piercing or slashing weapon you use it to make, so that’s an obvious choice when combined with a weapon that gets 18-20 crit range, or on a Lance for the freebie ×2 on charges (total ×5 on charge-crit). Other general multipliers, like Leap Attack, may also be useful. See an ubercharger handbook for a good list of those