I got these feats from
www.rpgcosmos.com
Weapon Mastery
Summary: You are more skilled with the use of the weapon you are specialised in.
Flavor: Choose one type of weapon. The character is especially good at attacking with this weapon.
Prerequisites: Weapon Specialisation, 9th level Fighter.
Benefit: The character adds +2 to his Base Attack Bonus with the weapon the character has mastered. If the weapon is a ranged weapon, the target must be within 30 feet.
Weapon Mastery (High)
Summary: You have trained in your weapon for many years,
becoming incredibly masterful with it.
Flavor: The character is so well trained with his mastered weapon, that he may make incredible feats of weaponsmanship.
Prerequisites: Weapon Mastery, Improved Critical, 13th level Fighter.
Benefit: The weapons damage die is increased by one, example: A Longsword does d8 damage normally, attaining this feat as a Longsword master would increase the damage die to d10. Furthermore this along with the BAB bonus from Weapon Mastery, and the damage bonus from Weapon Specialisation are no longer inhibited by a 30 ft range on ranged weapons.
Weapon Mastery (Grand)
Summary: After many years of training, the epitome of weapon mastery has been attained.
Flavor: The character has trained for so many years in the chosen weapon that they have reached the epitome of skill in it.
Prerequisites: Weapon Mastery (High), 17th level Fighter.
Benefit: The character' weapons critical damage modifier increase by x1, example: A longsword has a critical threat range of 19-20 with a damage multiplier of x2, after attaining this feat as a longsword high master, the weapon would have a x3 multiplier. Furthermore the weapons critical threat range is doubled, using the above example the range would increase to 17-20.
You can get more overpowered feats like these at
www.rpgcosmos.com