These are not yet Nick-approved for the most part.
Fighter and BAB
Unless otherwise stated, all of these may be selected as fighter bonus feats.
The Art of War
Requirements: Character level 5, Armor Proficiency (light), Weapon Focus (any martial or exotic weapon)
Benefit: Your base attack bonus increases by +1. This cannot increase your base attack bonus above +6. This feat may only be selected once.
Requirements: Character level 6, Armor Proficiency (light), Weapon Focus (any martial or exotic weapon), Power Attack
Benefit: You are considered to have four additional levels of fighter (with a maximum of 6) for the purposes of selecting feats. This feat may only be selected once.
Master of War
Requirements: The Art of War OR Monk level 6
Benefit: Your base attack bonus becomes +6.
One True Style
Prerequisites: Fighter level 6
Benefit: You may select feats with a requirement of up to fighter level 8, and with a base attack bonus requirement of up to +8.
Requirements: Character level 6
Benefit: Your ranger, barbarian, paladin, and monk levels are considered fighter levels for determining what feats you may select.
Note: This feat in particular might allow these classes to be too versatile when compared to pure fighters. It's just an idea, and this feat is one of those I'd definitely consider rejecting.
Requirements: Power Attack, Cleave, Armor Proficiency (light), base attack bonus +4
Benefit: You can fly into a rage once per day. In a rage, a you temporarily gains a +4 bonus to Strength, a +4 bonus to Constitution, and a +2 morale bonus on Will saves, but take a -2 penalty to Armor Class. The increase in Constitution increase your hit points by 2 points per level, but these hit points go away at the end of the rage when your Constitution score drops back to normal. (These extra hit points are not lost first the way temporary hit points are.) While raging, a you cannot use any Charisma-, Dexterity-, or Intelligence-based skills (except for Balance, Escape Artist, Intimidate, and Ride), the Concentration skill, or any abilities that require patience or concentration, nor can you cast spells or activate magic items that require a command word, a spell trigger (such as a wand), or spell completion (such as a scroll) to function. He can use any feat he has except Combat Expertise, item creation feats, and metamagic feats. A fit of rage lasts for a number of rounds equal to 3 + your (newly improved) Constitution modifier. You may prematurely end his rage. At the end of the rage, you lose the rage modifiers and restrictions and become fatigued for the duration of the current encounter.
Note: I personally think that precision-based damage (sneak attack damage) should not be allowed during a rage, either.
Requirements: Character level 6, Run, base attack bonus +6
Benefit: Your land speed is faster than the norm for your race by +10 feet. This benefit applies only when you are wearing no armor or light armor and carrying less than a medium load. Apply this bonus before modifying your speed because of any load carried or armor worn.
Note: Due to the awesome wording of the feat, we have no worries about stacking movespeed for barbs or clerics with the Celerity domain. This still allows monks to stack movespeed, as their movespeed bonus is an enhancement bonus. This is allowed in the actual game rules (by multiclassing barb/monk) so it seems reasonably okay.
Requirement: Eyes in the Back of your Head (Complete Warrior)
Benefit: You retain your Dexterity bonus to AC (if any) even if you are caught flat-footed or struck by an invisible attacker. However, you still lose your Dexterity bonus to AC if immobilized.
Note: Thank goodness for Complete Warrior giving me a good feat to build from.
Improved Uncanny Dodge
Requirement: Character level 5, Uncanny Dodge
Benefit: You can no longer be flanked. This defense denies a rogue the ability to sneak attack you by flanking, unless the attacker has at least four more rogue levels than than you have character levels.
Note: This needs more prereqs, as it is kind of strong for multiclass rogues.
Improved Inspire Courage
Requirement: Bard level 6
Benefit: Increases the benefits of your inspire courage to +2.
Bonus Domain Spells
Requirement: Cleric level 1
Benefit: Choose a domain available to your deity. You may now prepare spells from that domain in your domain spell slots.
Bonus Domain Power
Requirement: Bonus Domain Spells, character level 6
Benefit: Choose a domain for which you have the Bonus Domain Spells feat. You gain the domain power associated with that domain.
Note: You may want to limit a cleric to 3 or 4 domains, maximum; this is mainly so that CLR6 can get up to the same power level as a PrC cleric (more or less).
Requirement: Character level 6, ability to turn or rebuke undead
Benefit: Your cleric level for the purposes of turning undead is treated as four levels higher, with a maximum of your character level. This feat alters your base turning level, and feats or abilities which raise it (or rolling higher on your turning check) still apply normally after this feat.
Prerequisites: Character level 6, ability to cast 3rd-level divine spells, Wisdom 18, Healing 9 Ranks
Benefit: You can use Restoration, as the spell (paying the material component), with a casting time of 1 hour.
Magic, UMD, and Item Creation
Requirement: Use Magic Device 9 ranks, Knowledge: Arcana 5 ranks, Knowledge: Local 5 ranks
Benefit: You can read all types of arcane scrolls as though the spells are on your class list. You must still meet all attribute requirements required. If you do not meet the attribute requirements, you may still use UMD to emulate the appropriate attribute.
Requirement: Use Magic Device 9 ranks, Knowledge: Religion 5 ranks, Knowledge: Nature 5 ranks
Benefit: You can read all types of divine scrolls as though the spells are on your class list. You must still meet all attribute requirements required. If you do not meet the attribute requirements, you may still use UMD to emulate the appropriate attribute.