Voadam said:Use existing similar OGC spells or feats or make up your own ones for those niches that you can derive from OGC (such as the srd).
This would be very easy. See if you can tell what feat (from the SRD) this is:
Mighty Attack
At the expense of accuracy, you can make your melee attacks hit harder.
Prerequisite: Base attack bonus +1 or higher, Strength score must be 13 or higher.
Benefit: As a free action on your turn (before you've made any attack rolls) you can voluntarily take a penalty to your melee attack rolls (ranging from -1 up to the value of your base attack bonus). If you hit despite the penalty, you get to add the value of the penalty to your damage roll. These penalties and bonuses apply until your next turn.
Special: A fighter can select Mighty Attack as one of his bonus feats. Light weapons don't let you get the bonus damage on attacks but you still have to take the penalties. (This provision doesn't apply to unarmed attacks or natural attacks.) If you're wielding a single weapon with two hands, you can add the damage to bonus twice.
That took something like a minute to figure out how to rephrase and another minute to type out. If it's only a very few things you might consider making your own statistically close versions like that.