If the items below are not overpowered, I don’t know what is:
Lilarcor +3
Properties:
THAC0: +3.
Damage: 1D10 +3
Equipped Abilities: Immunity to Charm and Confusion.
Weight: 10.
Speed Factor: 8.
Requires: 14 Strength.
Adjatha the Drinker +2
Properties:
Equipped Ability: Wielder is immune to Charm and Domination spells.
Special Ability: Each hit heals the wielder of 1 hit point damage.
THAC0: +2.
Damage: 1D8 + 2.
Weight: 3.
Speed Factor: 3.
Requires: 6 Strength.
You see, all the cool effects and little details don’t matter much if they are going to make you into a unstoppable killing machine.
That's what you came up with? Look, if you're gonna list OP shit do so, pls.
Robe of Vecna: insane casting time reduction, stacks with the ammy: get your spells off long before anyone else. A munchkin's dream.
Celestial Fury +3: Stuns almost anything, even MR-immunes. Best one-handed wield in SoA. Also the best backstabbing weapon until Staff of the Ram.
Flail of Ages +5: Slows almost anything, even MR-immunes. Elemental damage penetrates stoneskin to disrupt spellcasting. This weapon slays any foe, excepting magical golems (an extremely rare enemy that is immune to magical weapons). Best one-handed wield in BG2, ToB included.
Belm/Kundane: off-hand wields that bestow +1 ApR. This is how you get 10 ApR even before GWW HLA. Tuigan is a bow that gives +1 ApR.
Crom Faeyr: 25 Strength, turns anyone into a Titan. Dual-wield with Crom and solo BG2 with a warrior.
Defender of Easthaven: 20% DR, stacks with Hardiness and innate DR for 80% total DR.
Foebane +5: Demon-killer. heal 4d4 HP per round. dual-wield with purifier. 'nuff said.
Blackrazor +3: stacking on-hit level drain, plus heals/hastes wielder.
Vhailor Helm: self-simulacrum, you munchkin faggot!
Staff of the Magi +5: at-will invis, hits as +5, lvl 30 on-hit dispel, lots of other bullshit abilities.
Staff of the Ram +6: A kensai/thief dual chunks almost anything with this.
Mace of Disruption +2: Vamp-vanquisher. Bypasses Lich's mantle because it hits as +5. Bane of Demi-Lich, Kangaxx.
Shield of Balduran +3: Eats Beholders for brekky.
Shield of Harmony +2: Laugh in the face of common negative statuses.
Carsomyr +6: 1d12 +6, +6 vs. chaotic evil. on-hit Dispel, and wieldable by pallys and UAI thieves.
Gram the Sword of Grief +5: drain bosses 10lvls/rnd.
Psion's Blade +5: anti-illithid wield.
Ixil's Spike +6: capable of impaling bosses, very dmging wield.
Spear +3: Impaler: this is what you wield b4 you get Ixil's, +10 piercing dmg for romping SoA.
Axe of the Unyielding +5: 10% vorpal, its 3 HP/round regen stacks with Gaxx.
Ravager +6: 1d10 +6 +3d6. In addition, Sarevok has 15% vorpal on any non-boss wielding this.
List is not exhaustive, not by a long shot. Not to mention all the Str girdles, magic protection items, OP armors, perma-haste items (whole party has perma-haste) etc.