This is a list of epic feats that are not available upon reaching levels above 20. Aditionally, bonus feats gained from class levels (like those of a fighter, wizard or rogue) cannot be used to purchase any epic feats at all.
Armor Skin
Combat Insight
Epic Weapon Focus
Epic Weapon Specialization
Epic Spell Focus
Improved Spell Resistance
Overwhelming Critical
Improved Sneak Attack
Improved Stunning Fist
Bane of Enemies
Epic Barbarian Rage
Epic Wild Shape: Dragon
Epic Spell: Mummy Dust
Epic Spell: Dragon Knight
Epic Spell: Hellball
Epic Spell: Epic Mage Armour
Epic Spell: Ruin
Epic Spell: Mass Fowl
Eldritch Master
Expose Weakness
Persistent Spell
Thundering Rage
Song of Requiem
Hymn of Requiem
Dragon Companion
Epic Spell: Vampiric Feast
Epic Spell: Epic Gate
Epic Spell: Damnation (Warlock)
Epic Spell: Entropic Husk (Warlock)
Epic Spell: Epic Gate (Warlock)
Epic Spell: Hellball (Warlock)
Epic SPell: Vampiric Feast (Warlock)
Epic Precision
Automatic Still Spell (> level 3)
Automatic Silent Spell (> level 3)
Automatic Quicken Spell (> level 3)