The discussions on the E6 thread have prompted me to post one new feat and modify several more for E6.
Improved Critical (General)
Prerequisites: Fighter 6, BAB + 6, Weapon Focus, Power Critical (Complete Warrior)
Benefit: Choose a weapon you have Weapon Focus and Power Critical feats for to apply this feat to. When using this weapon your threat range is doubled (20 to 19-20, 19-20 to 17-20, etc.)
Special: You may take this feat multiple times. Each time you do it applies to a different weapon.
Greater Weapon Focus (Fighter)
Prerequisites: Fighter 6, Weapon Focus and Weapon Specialization
Benefit: Choose a weapon you have the Weapon Focus and Weapon Specialization feats for. Your bonus to attack rolls with this weapon increases to +2.
Special: You may take this feat multiple times. Each time you do, it applies to a different weapon.
Greater Weapon Specialization (Fighter)
Prerequisites: Fighter 6, Weapon Focus, Weapon Specialization, Greater Weapon Focus
Benefit: Choose a weapon you have the Weapon Focus, Weapon Specialization, and Greater Weapon Focus feats for. Your bonus to damage rolls with the weapon increases to +4.
Special: You may take this feat multiple times. Each time you do, it applies to a different weapon.
Sweeping Strike (Fighter)
Prerequisites: Fighter 6, BAB +6, Str 17 +,Int 13 +, Balance 4 ranks, Combat Expertise, Cleave, Great Gleave, Improved Bull Rush, Improved Sunder, Power Attack
Benefit: You must choose two adjacent opponents at the beginning of your turn that you threaten. All of the melee attacks you make during your turn apply to both opponents.
This feat basically replicates the Sweeping Strike class ability of the Warmind PrC, which is out of reach for E6 characters.