Similar effects that do not share a name will stack, such as 
Quicksilver Sash and 
Mikael's Crucible. Some item effects are named but unique to an item.
List of effects
Below is a list of all named effects and the items to which they belong. Note that each effect may or may not be shared my multiple items.
At Wit's End
At Wit's End grants bonus on-hit damage and healing.
The following items grant At Wit's End:
Awakened Dragon
Awakened Dragon grants bonus attack speed and reduces basic abilities cooldown when basic attacking.
The following items grant Awakened Dragon:
Awe
Awe grants bonus stat based on your maximum mana, while also refunding a part of your mana spent.
The following items grant Awe:
Blackout
Blackout items reveal nearby wards and traps.
The following items grant Blackout:
Bloodlust
Bloodlust items restore health when dealing physical damage.
The following items grant Bloodlust:
Blood Pursuit
Blood Pursuit grants bonus stats while near one of fewer visible enemy champions.
The following items grant Blood Pursuit:
Challenging Smite
Challenging Smite items grant 
Challenging Smite.
The following items grant Challenging Smite:
Chilling Smite
Chilling Smite items grant 
Chilling Smite.
The following items grant Chilling Smite:
Cleave / Crescent
Cleave causes the champion's basic attacks to deal physical splash damage to units around the target. Crescent is an active effect that causes the champion to either deal physical damage in an area around them, or enhance the effects of Cleave.
The following items grant Cleave:
The following items grant Crescent:
Cold Steel
Cold Steel causes basic attacks against you to 
cripple the enemy champion.
The following items grant Cold Steel:
Conduit
Conduit binds to an ally without an existing Conduit.
The following items grant Conduit:
Crushing Blow
Crushing Blow items apply bonus on-hit damage.
The following items grant Crushing Blow:
Cursed Strike
Cursed Strike items apply 
Grievous Wounds.
The following items grant Cursed Strike:
Dissolve
Dissolve grants the user magic penetration.
The following items grant Dissolve:
Dissonance / Harmony
Dissonance grants ability power for every base mana regeneration, while also disabling Harmony on other items wielded.
Harmony grants base health regeneration for every additional base mana regeneration. The effect itself doesn't multiply when having both 
Chalice of Harmony and Mikael's Crucible but it takes into account the additional base mana regeneration provided by both items and acquires total respective amount of additional base health regeneration.
The following items grant Dissonance:
The following items grant Harmony:
Do or Die / Dread
Do or Die grants Glory for champion kills and assists and reduces Glory upon death. Glory is utilized by Dread to gain ability power and possibly bonus movement speed.
The following items grant Do or Die:
The following items grant Dread:
Dreadnought
Dreadnought items charge bonus movement speed when moving.
The following items grant Dreadnought:
Echo
Echo causes you to gain charges upon moving or casting. At 100 charges, the next instance of ability damage you deal will expend all charges to deal bonus magic damage to the first enemy hit and summon up to 3 lesser bolts that target nearby enemies, prioritizing enemies damaged by the ability and champions over minions.
The following items grant Echo:
Electroshock
Electroshock adds bonus magic damage on-hit to the next 
Energized attack, and the attack bounces the several other targets.
The following items grant Electroshock:
Energized
Energized causes you to gain Energize stacks from movement and basic attacks. At 100 Energize stacks, your next basic attack deals bonus magic damage and possibly has other effects. The damage and effects from Energized stack from multiple items. The Energized attack can trigger against turrets.
The following items grant Energized:
Enhanced Movement
Enhanced Movement grants the user bonus movement speed. Note: this named passive effect is redundant, as only one boots item can be owned.
The following items grant Enhanced Movement:
-
Boots of Speed
- Berserker's Greaves
- Boots of Mobility
- Boots of Swiftness
- Ghostwalkers
- Ionian Boots of Lucidity
- Mercury's Treads
- Ninja Tabi
- Slightly Magical Boots
- Sorcerer's Shoes
Eternity
Eternity transforms a portion of damage taken from champions into mana. Also transforms a portion of mana spent into health, up to an amount per cast (toggle spells heal for up to an amount per second).
The following items grant Eternity:
Executioner
Executioner grants the user the ability to inflict Grievous Wounds on enemy champions upon dealing physical damage.
The following items grant Executioner:
Frostfire Covenant
Frostfire Covenant makes basic attacks against a burning enemy ignite your frost storm to deal bonus magic damage per second and slow for 3 seconds.
The following items grant Frostfire Covenant:
Giant Strength
Giant Strength items grants bonus attack damage.
The following items grant Giant Strength:
Haste
Haste items grants additional cooldown reduction.
The following items grant Haste:
Hextech
Hextech items grants a variety of active and passive effect, and even though they have different names, they share the same cooldown.
The following items grant Fire Bolt:
The following items grant Frost Bolt:
The following items grant Lightning Bolt:
The following items grant Magic Bolt:
Icy
Icy slows an opponent's movement speed. Slows from items with Icy do not stack with each other (only the strongest slow will apply).
The following items provide Icy:
Immolate
Immolate deals magic damage to surrounding enemies every second.
The following items provide Immolate:
Jolt
Jolt adds bonus magic damage on-hit to the next Energized attack.
The following items grant Jolt:
Last Whisper
Last Whisper grants the user armor penetration.
The following items grant Last Whisper:
Lifeline
Lifeline grants you a type of shield upon taking damage that would decrease you below a threshold.
The following items grant Lifeline:
Lifegrip
Lifegrip grants bonus stats until out-of-combat.
The following items grant Lifegrip:
Madness
Madness items grants increased damage when in-combat with enemy champions.
The following items grant Madness:
Mana Charge
Mana Charge increases the user's maximum mana, upon spending mana, up to a cap.
The following items grant Mana Charge:
Mana Shield
Mana Shield drains mana to shield the user for a few seconds.
The following item grants Mana Shield:
Metallicize
Metallicize increases health for a few seconds, with an increased amount while Stone Skin is active.
The following items grant Metallicize:
Monster Hunter
Monster Hunter gives bonus experience when killing jungle monsters.
The following items grant Monster Hunter:
Nightstalker
Nightstalker items grant bonus on-hit damage after not being seen by champions.
The following items grant Nightstalker:
Paralyze
Paralyze adds a slow and bonus magic damage on-hit to the next Energized attack.
The following items grant Paralyze:
Path of Iron
Path of Iron items leave a trail that grant allies bonus movement speed.
The following items grant Path of Iron:
Progress and Glorious Evolution
Progress allows 
Viktor to upgrade one of his abilities.
Glorious Evolution automatically upgrades Viktor's 
Chaos Storm.
The following items grant Progress:
The following items grant Glorious Evolution:
Quest
Quests are unique effects that upgrades the item when having generated enough gold with that item.
The following items grant Quest:
- Relic Shield / Targon's Buckler
- Steel Shoulderguards / Runesteel Spaulders
- Spellthief's Edge / Frostfang
- Spectral Sickle / Harrowing Crescent
Quicksilver
Countering Airborne CC
The following items grant Quicksilver:
Notes:
- Quicksilver will not remove persistent areas of effect.
- If Quicksilver removes Veigar's Event Horizon, the user will gain immunity to that instance of the skill.
- Quicksilver will remove the slow of Chum the Waters but the fish will still remain attached and the shark will still appear.
- Quicksilver's interaction with leashed effects is somewhat complex, and it would appear that each is coded individually:
- Will entirely remove: Ethereal Chains, Soul Shackles, Death Sentence, Fear Beyond Death
- Will remove the crowd control: Nether Grasp, Infinite Duress
- Will not remove: Drain, Unspeakable Horror
- This includes any damage it applies and secondary effects.
- Will entirely remove:
Mikael's Crucible provides a similar effect, allowing you to remove crowd control from the target ally. Note that Mikael's Crucible does not remove damage over time or other debuffs, and it cannot be activated while unable to activate abilities (such as a 
silence).
Rage
Rage causes basic attacks to grant bonus movement speed for a few seconds on-hit. Kills on any unit grant more bonus movement speed for a few seconds.
The following items grant Rage:
Sharpshooter
Sharpshooter adds bonus attack range and bonus magic damage on-hit to the next Energized attack.
The following items grant Sharpshooter:
Shock
Shock is a passive effect that causes your single target abilities and basic attacks on champions (on-hit) to consume mana to deal bonus physical damage.
The following item grants Shock:
Slow Resist
The following item grants Slow Resist:
Sorcery
Sorcery items deal bonus true damage to enemy champions and turret.
The following items grant Sorcery:
Spectral Pursuit
Spectral Pursuit items summons ghosts that slows enemy champions.
The following items grant Spectral Pursuit:
Spectral Waltz
Spectral Waltz grants bonus movement speed and 
ghosting when hitting a enemy champion.
The following item grants Spectral Waltz:
Spellblade
- For the removed item, see Moonflair Spellblade
- For the removed mastery, see Spellsword
Spellblade causes your next basic attack or on-hit effect to deal bonus damage after using an ability.
The following items grant Spellblade:
Notes:
- In the event you own multiple spellblade items, only one attack bonus applies, to which the order of priority is:
- Lich Bane, Trinity Force, Iceborn Gauntlet, and Sheen.
-
- The area of effect slow is not considered part of the "Spellblade" effect, and is instead classified as Icy. If you own both Iceborn Gauntlet and a higher priority Spellblade item (i.e. Lich Bane and Trinity Force), you will trigger the higher priority's damage component while still triggering the area of effect slow.
Spell Shield
Spell Shield is a passive effect that grants a 
spell shield on the champion.
The following items grant Spell Shield:
Spoils of War
Spoils of War: Melee autoattacks execute minions below a certain amount of health. Killing a minion by any means heals yourself and the nearest allied champion and grants them kill gold. These effects require a nearby allied champion and consume a charge.
The following items grant Spoils of War:
Stasis
Stasis is an active ability that puts your champion into 
stasis, making yourself invulnerable and untargetable, but also renders you unable to perform any actions for a few seconds.
The following items grant Stasis:
Sterak's Fury
Sterak's Fury grants increased size and bonus tenacity for a few seconds.
The following item grants Sterak's Fury:
Stone Skin
Stone Skin grants additional resistances while near multiple enemy champions.
The following items grant Stone Skin:
Tenacity
suppression, stasis, and 
displacements).
The following items grant Tenacity:
Thorns
Thorns items returns damage to enemies who basic attack their owner.
The following items grant Thorns:
Tooth and Nail
- Tooth deals bonus magic damage over time and restores health against monsters.
- Nail grants bonus damage on-hit against monsters.
- Tooth and Nail grants bonus on-hit damage, deals bonus magic damage over time, and restores health against monsters. It also grants bonus mana regen while in the jungle or river, based on missing mana.
The following items grant Tooth:
The following items grant Nail:
The following items grant Tooth and Nail:
Torment
Torment items deals bonus damage over time when hitting an unit with magic damage.
The following items grant Torment:
Touch of Death
Touch of Death items grants magic penetration.
The following items grant Touch of Death:
Tribute
Tribute items deals bonus damage and grant gold when damaging an enemy champion or structure.
The following items grant Tribute:
Warding
Warding grants the user a number of charges, which are refreshed by upon returning to the fountain. You can consume a charge to place a 
Stealth Ward at the target location.
The following items grant Warding:
- Targon's Buckler / Bulwark of the Mountain
- Runesteel Spaulders / Pauldrons of Whiterock
- Frostfang / Shard of True Ice
- Harrowing Crescent / Black Mist Scythe
Warmog's Heart
Warmog's Heart restores health per second if the champion hasn't taken damage for a duration.
The following items grant Warmog's Heart:
Wind's Fury
Wind's Fury causes basic attacks to fire bolts at up to 2 enemies near the target, each dealing physical damage.
The following items grant Wind's Fury:
Archive
- Archive (Removed named effects)
