After realizing how many methods there are of stacking attack penalties on enemies in this thread, I've decided to put together a guide to put them all in one place for handy reference. I hope you like tables. Also, there will be a stronger focus on at-will attack penalties, because that's more fun.
The beauty of these builds is that a single hit will greatly cripple any enemy without an automatic damage mechanism - if you have good defenses, monsters will only hit on an 10 or better, and if they have a -9 to attack, they're practically helpless bar critical hits. Plus, there's something so satisfying about imagining a rogue dancing around an enemy taunting him with "hit me, c'mon, hit me!".
Powers
Show
| Attack | Class | Stat | Range | Target | Keywords | Penalty | Against | Duration | Hit/Effect |
| Enfeebling Strike | Paladin | Cha vs. AC | Melee | Creature | Weapon | -2 if marked | All | EoYNT | Hit + Mark |
| Overwhelming Strike | Avenger | Wis vs. AC | Melee | Creature | Weapon | [feat] | |||
| Disheartening Strike | Rogue | Dex vs. AC | Melee or Ranged | Creature | Rattling, Weapon | -2 rattling | All | EoYNT | Hit |
| Beguiling Strands | Wizard | Int vs. Will | Blast 5 | Enemy | Arcane, Charm, Implement, Psychic | [feat] | |||
| Sunspray Dance | [feat, human] | Highest vs. AC | Melee | Creature | Weapon | -2 | All | SoYNT | Hit |
| Chilling Cloud | Wizard | Int vs. Fort | Burst 1 in 10 | Enemy | Arcane, Implement | -2 in area | All | EoYNT | Effect |
| Dire Radiance | Warlock | Cha/Con vs. Fort | Ranged 10 | Creature | Arcane, Implement | [feat] | |||
| Eldritch Strike | Warlock | Cha/Con vs. AC | Melee | Creature | Arcane, Weapon, MBA | [feat] | |||
| Biting Swarm | Seeker | Wis vs. AC | Ranged | Creature | Primal, Weapon, RBA | -2 | All, adjacent | SoYNT | Hit |
| Vicious Mockery | Bard | Cha vs. Will | Ranged 10 | Creature | Arcane, Charm, Implement, Psychic | -2 | All | EoYNT | Hit |
| Brash Strike | Fighter | Stre+2 vs. AC | Melee | Creature | Weapon | [feat] | |||
| Singing Strike | Cleric | Wis vs. AC | Melee | Creature | Thunder, Weapon | -2 | All | EoYNT | Effect |
| Dishearten | Psion | Int vs. Will | Burst 1 in 10 | Creatures | Implement, Psionic, Psychic | -2 | All | EoYNT | Hit |
| Illusory Ambush | Wizard | Int vs. Will | Ranged 10 | Creature | Arcane, Illusion, Implement, Psychic | -2 | You | EoYNT | Hit |
| Intellect Snap | Battlemind | Con vs. Will | Melee | Creature | Psychic, Weapon | [feat] | Hit, daze | ||
| Mantle of the Infidel | Invoker | Wis vs. Will | Ranged 20 | Creature | Implement | -4 | Allies | Marked | Hit, mark |
| Fallen Needle | Monk | Dex vs. Reflex | Melee touch | Creature | Implement, Psionic | -2 | You | EoYNT | Hit |
| Ego Whip | Psion (7) | Int vs. Will | Ranged 10 | Creature | Implement, Psionic, Fear, Psychic | -2 | All, Def | EoYNT | Hit |
Feats
Show
| Name | Tier | Prerequisite | Penalty | Against | Duration | Trigger |
| Power of Madness | Heroic | Divine, madness domain | -1 | All | EoYNT | Hit with Enfeebling Strike, Overwhelming Strike, Righteous Brand or Visions of Blood |
| Whip Training | Heroic | Dex 13 | -2 | Choice | EoYNT | Hit with whip |
| Impending Doom Style | Heroic | Martial, trained in Intimidate | -2 | All | EoYNT | Hit twice with Twin Strike, Hit with Riposte of Riposte Strike |
| Arena Specialist | Heroic | Int 13, martial class | -2 | All | EoYNT | Hit with Disheartening Strike (one adjacent enemy) |
| Draji Palatial Practice | Heroic | Martial, trained in Intimidate | -2 | All | EoYNT | Hit with Circling Strike, Deft Strike, Furious Smash, Sure Strike |
| Sunspray Warrior | Heroic | Human, Sunspray Heritage | -2 | All | EoYNT | Hit with Sunspray Warrior |
| Underhanded Tactics | Heroic | Rogue, Sneak Attack | -2 | All | EoYNT | Deal Sneak Attack, forgo 1 die |
| Disheartening Ambush | Paragon | Rogue, Sneak Attack | -2 | All | EoYNT | Deal Sneak Attack, forgo 1 die (rattling) |
| Mark of Warding | Heroic | Dragonmark | -3 | Allies | While marked | If marked |
| Eladrin's Challenge | Heroic | Eladrin, fighter | -3 | Allies | While marked | If marked, wielding a longsword or any spear |
| Daunting Challenge | Paragon | Fighter, Combat Challenge | -3 | Allies | While marked | If marked |
| Group Defense | Heroic | Half-elf, Paladin | +1 Def | Allies | While marked | If marked |
| Arcane Familiar - Gallant Hawk | Heroic | Any arcane | -3 | Allies | While marked, adjacent | If marked, adjacent |
| Ironstar Student | Heroic | Fighter, ranger, warlord, flail/mace proficiency | -2 | All | EoYNT | Hit with Brash Assault, Marauder's Rush, Reaping Strike with CA and flail/mace |
| Beguiling Enchantment | Heroic | -2 | You | EoINT | Hit with charm power | |
| Bloodhunter’s Dread | Heroic | Tiefling | -2 | You | EoYNT | Hit bloodied enemy |
| Fearsome Flurry | Heroic | Foulborn Heritage, monk, Flurry of Blows | -2 | All | EoYNT | Forgo normal flurry damage |
| Distracting Shield | Heroic | Wis 15, fighter, Combat Challenge, shield | -2 | All | SoYNT | Hit with CC |
| Distracting Companion | Paragon | Ranger, Beast Master | -2 | You, Beast | SoYNT | Hit quarry next to companion |
| Psychic Lock | Paragon | -2 | Next | Ever | Hit with psychic keyword | |
| Defending Dabbler | Heroic | Half-elf | -2/3 | Allies | While marked, EoYNT | Hit with Dilettante |
| Dizzying Mace | Paragon | Fighter | -Con | All | While dazed | Hit and daze enemy with mace |
| Ulban’s Flare | Heroic | Warlock, star pact | -2 | All | EoYNT | Hit with Dire Radiance with concealment |
| Hammer Shock | Paragon | Martial, trained in Intimidate | -2 | All | EoYNT | Hit with MBA with hammer (rattling) |
| Protective Hex | Paragon | Warlock, Warlock’s Curse | -2 | Allies | EoYNT | Hit cursed enemy (against close and melee only) |
| World Serpent’s Grasp | Heroic | -2 | All | Until stands | Hit slowed or immobilized enemy (prone) | |
| Polearm Momentum | Heroic | Dex 15, Wis 15, fighter | -2 | All | Until stands | Push/slide target 2 squares with polearm/spear attack (prone) |
Items
Show
| Name | Type | Property |
| Harmony Blade | Heavy blade | Hit target with both hands, enemy takes -2 penalty, You, EoYNT |
Other Useful Feats
Show
| Name | Tier | Prerequisites | Effect |
| Mindbite Scorn | Heroic | Warlock's Curse, sorcerer-king pact | Extra 1d6 curse damage, psychic keyword |
| Moonbow Dedicate | Heroic | Worship Sehanine | Use shortbow as implement for divine/arcane powers (for mindiron) |
| Enlarge Spell | Heroic | Wis 13, Wizard | Add 1 to wizard at-will/encounter blast or burst for -2 damage per die |
| Resounding Thunder | Paragon | Add 1 to any blast or burst with thunder keyword | |
| Arcane Admixture | Paragon | Any arcane | Add acid, cold, fire, lightning or thunder keyword to one arcane attack |
| Versatile Master | Paragon | Half-elf | Dilettante becomes at-will, qualifies for Underhanded Tactics or Warlock’s Curse, Defending Dabbler |
Ways of getting Psychic keyword for Psychic Lock
Show
| Name | Type | Effect |
| Mindiron Weapon | Bows, Crossbows | Half the damage dealt with this weapon is psychic damage |
| Sorrowsong Blade | Heavy Blade | Half the damage dealt with this weapon is psychic damage |
| Githyanki Silver Weapon | Heavy Blade | All damage dealt by this weapon is psychic damage |
| Mindbite Scorn | Feat | Adds psychic keyword to warlock attacks |
Class/Paragon Path Features
Show
| Name | Tier | Prerequisite | Feature |
| Illusion Apprentice | Class | Mage | Illusion Apprentice: Hit with illusion power, -2 to Next attack roll |
| Ruthless Ruffian | Class | Rogue | Use club and mace for rogue powers, qualify for dizzying mace |
| Messenger of Peace | PP | Cleric, Diplomacy | Aura of Peace (16): Enemies within 2 squares of you take a -2 penalty, All, Always |
| Shadow Assassin | PP | Rogue | Shadow Assassin’s Riposte (11): When missed, deal enemy Dex damage |
| Devout Warpriest | PP | Warpriest | Transcendent Blessing (Oghma, 11): Singing Strike also immobilizes until EoYNT |
| Stygian Adept | PP | Ardent | Fearsome Zone (16): Enemies in zones of your psionic powers take a -2 penalty, All |
Other Notes
Dizzying Mace may or may not work with Overwhelming Impact, as “using” a mace may or may not include having a mace in your off-hand. Some rods also count as maces, for adding Dizzying Mace on Warlock implement powers and so on.
