Datamined changes from current PBE release. Be aware that these changes are tentative and they might be changed or even reverted prior to the live patch.
Datamining only captures numerical changes. It doesn't capture changes to mechanics and bugfixes that may also significantly affect balance.
Due to the nature of how the datamining works it may also includes some of the changes that are already added to the live version in the most recent patch.
Updated: Dec 10 12PM

Leona
Passive: Reduce instances of incoming damage by 15/30/60 (
).Active: Call down sun beams on the 3 nearest enemies, Stunning them for 1 second and dealing 80/120/200 (
) magic damage. Wound and 1% Burn them for 4 seconds.. Passive: Reduce instances of incoming damage by 15/30/60 (
).Active: Call down sun beams on the 3 nearest enemies, Stunning them for 1 second and dealing 80/120/200 (
) magic damage. Wound and 1% Burn them for 4 seconds. Passive: After dealing ability damage to an enemy, gain Stardust. Stadust makes The Skies Descend more powerful. Active: Crash a star on target, dealing 350/615/5000 (
) magic damage in a 2 hex radius.Stardust Upgrades:15: Create a shockwave that deals 50/75/1000 (
) additional magic damage in a 3 Hex radius.60: The star crash deals 12% more damage.100: Shockwave increases to a 4 hex radius.175: Knock up targets in the star crash for 2 seconds.250: Shockwave increases to 10 radius.400: The star crash deals 25% bonus true damage.700: Also call down a meteor storm that deals 1000/1500/9999 (
) magic damage split between living enemies.1988: Summon a black hole at the epicenter, instantly killing enemies within. Passive: After dealing ability damage to an enemy, gain Stardust. Stardust makes The Skies Descend more powerful. Active: Crash a star on target, dealing 350/615/5000 (
) magic damage in a 2 hex radius.Stardust Upgrades:15: Create a shockwave that deals 50/75/1000 (
) additional magic damage in a 3 Hex radius.60: The star crash deals 12% more damage.100: Shockwave increases to a 4 hex radius.175: Knock up targets in the star crash for 2 seconds.250: Shockwave increases to 10 radius.400: The star crash deals 25% bonus true damage.700: Also call down a meteor storm that deals 1000/1500/9999 (
) magic damage split between living enemies.1988: Summon a black hole at the epicenter, instantly killing enemies within. 
Fiddlesticks
Teleport into the largest cluster of enemies and Stun them for 1.25/1.25/99 seconds. Begin losing 22 mana per second. While casting, deal 100/150/6666 (
) magic damage per second to all enemies within a 2 hex radius. The closest 2 enemies take 33% more damage. Teleport into a large cluster of enemies within 2 hexes and Stun them for 1.25/1.25/99 seconds. Begin losing 22 mana per second. While casting, deal 100/150/6666 (
) magic damage per second to all enemies within a 2 hex radius. The closest 2 enemies take 33% more damage. 
Bilgewater

Shadow Isles
Whenever ANY champion dies, gain Souls (
). Shadow Isles champions' Abilities are uniquely empowered based on the number of Souls you have.Shadow Isles champions gain Attack Damage and Ability Power.Souls Collected: 0 
Whenever ANY champion dies in a player combat, gain Souls (
). Shadow Isles champions' Abilities are uniquely empowered based on the number of Souls you have.Shadow Isles champions gain Attack Damage and Ability Power.Souls Collected: 0 

Eternal Pact
Combat start: Form a pact with the highest Health ally, if they die, gain 10 Mana regen and 40% Ability Power.When the ally uses their ability, gain 6 Mana. Every 6 seconds, shield your ally for 150% of the holder's Ability Power. Combat start: Form a pact with the highest Health allied champion, if they die, gain 10 Mana regen and 40% Ability Power.When the ally uses their ability, gain 6 Mana. Every 6 seconds, shield your ally for 150% of the holder's Ability Power. 
Birthday Reunion
Gain a random 2-star 2-cost champion. When you reach Level 6, gain a Thief's Gloves. When you reach Level 9, gain a random 2-star 5-cost champion.Inkborn Fables Tactician's Crown, 2024 Gain a random 2-star 2-cost champion. When you reach Level 7, gain a Thief's Gloves. When you reach Level 9, gain a random 2-star 5-cost champion.Inkborn Fables Tactician's Crown, 2024 
Bronze For Life II
Your team gains 2.5% Damage Amp and 2% Durability for each Bronze-tier trait.
Your team gains 2.5% Damage Amp and 4 Armor and Magic Resist for each Bronze-tier trait.

Evolve and Overcome
For every 5 enemies that Mutated Void allies takedown, gain 2 XP. Gain a Cho'Gath and a 2-star Kog'Maw. (Takedowns: 0/5)Void provides unique Mutations. For every 5 enemies that Mutated Void allies takedown, gain 2 XP. Gain a Cho'Gath and a 2-star Kog'Maw. 0Void provides unique Mutations. 
Infinity Protection
Gain 4 Gold now. On 3-7, gain an Infinity Force. Infinity Force gives allies in the same row a 15% Health shield.Monsters Attack Championship, 2023 Gain 4 gold now. On Stage 3-7, gain an Infinity Force. Infinity Force gives allies in the same row a 15% Health shield.Monsters Attack Championship, 2023 
Late Game Scaling
Gain 2 XP every round. Your 5-cost champions gain 12% Health and 12% Attack Speed.CyberCity Tactician's Crown, 2025 Gain 2 XP at the start of player combat rounds. Your 5-cost champions gain 12% Health and 12% Attack Speed.CyberCity Tactician's Crown, 2025 
Slice of Life
Twice per stage, gain a random champion. Its cost increases by Stage. This effect ends after receiving 1 5-cost champions.
Twice per stage, gain a random champion. Its cost increases by Stage. This effect ends after receiving 1 5-cost champion.

The Axiomata
Gain 3 random elemental hex augments. Future augment rounds instead grant you 1 random elemental hex and gold based on the augment's tier.
Gain 3 random elemental hex augments. Future augment rounds instead grant you items and gold based on the augment's tier.

Trials of Twilight
Gain a Xin Zhao. Your strongest Xin Zhao constantly strikes nearby enemies and executes enemies. After 5 player combats as a 3-star, unlock Zaahen. He replaces Xin Zhao and takes his items.
Gain 2 Xin Zhao. Your strongest Xin Zhao constantly strikes nearby enemies and executes enemies. After 5 player combats as a 3-star, unlock Zaahen. He replaces Xin Zhao and takes his items.

Two Much Value
Gain 1 reroll for every 2 unique 2-cost champions fielded last combat. Gain 2 2-cost champions.
Gain 1 reroll for every 2 unique 2-cost champions fielded last player combat. Gain 2 2-cost champions.