Band of Bastards
The basic rules for Action Points are found in Eberron (ECS) and Unearthed Arcana (UA), but I’ve expanded or modified them a little. I’m a bit more generous with gaining and using them.
What are they?
Action Points represent that special knack heroes have for changing the world around them, surviving the impossible, and accomplishing things beyond mere mortals. They may be used to modify any roll (attack, skill, damage, save, etc), temporarily increase AC, emulate feats, offset spell costs and cast extra spells, avoid death, gain extra uses of class abilities and spell-like abilities, and so on.
Typically, only one AP may be spent on any given roll; further modifying a roll increases the AP cost accordingly. For example, if you wish to benefit from two AP, the actual cost is 3 AP. Benefitting from three AP costs 5 AP, and so on.
To modify any roll, simply declare that you want to spend an Action Point before the results are known. Up to level 7, each AP is worth 1D6, levels 8 thru 14 are worth 2D6, and levels 15+ are worth 3D6. When the dice are rolled, only count the highest die roll and apply it to the original roll (attack, etc). The only exception to this are damage rolls, which benefit from the whole roll.
You may modify any attack roll, skill check, initiative roll, saving throw, damage roll, caster level check, ability check, critical hit confirmation, spell effect (cure spells and such), and more.
Activate Class Ability
Gain another daily use of a class ability, such as Rage, Wildshape, or Turn Undead.
Doubles the benefit of fighting defensively for one round.
Boost Armor Class
Increase your AC for one incoming attack in the hopes of turning it away.
Gain the use of a feat for one round. If the feat’s feat or class requirements aren’t met, the AP cost increases by 1 per missing feat. For example, emulating Great Cleave without having Cleave costs 2 AP. If you have Cleave already, the cost to emulate Great Cleave is 1 AP.
Emulating feats is arguably the most beneficial thing you can do with AP, so be clever and take advantage of it.
Gain another move, move-equivalent, or standard action.
May spend AP to cast a spell. The cost is equal to the spell’s level.
Increase the effective caster level by two (2) levels.
Use AP to offset cost of metamagic application (see Magic).
Spell Save Bonus
Increase a spell’s save DC.
Increase your Caster Level check to overcome Spell Resistance.
When dying, spend AP to stabilize. The cost is equal to half your negative hit points, but hey, at least you’ll live.
Take Action When Dying
May spend an AP to take a single action in a round of dying. If the action is exerting (move or standard), the PC takes 1 hit point of damage. Move-equivalent actions typically aren’t exerting.
Many feats can be improved by spending AP. In general, their numeric benefit is doubled. In most cases, the benefit lasts for 1 round. For example, if you have Improved Grapple, you can spend 1 AP to double the grapple bonus that the feat normally grants from +4 to +8.