Haven unique pairings

Every unique in Minecraft Dungeons II, what its fixed effect does, and the gear, artifacts, talismans and enchantments most likely to make it strong. These are leads to test in game, worked out from what the item sites say each item does. Nothing here has been tested yet.

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Pair with is the list to test, strongest-looking first. Names in brackets are the effect that piece brings.
Test in game is the open question that decides whether the pairing works. That answer is what your video adds.
Same effect on lists other uniques with the identical effect. "No name listed" means the sites give the effect but not its name. Tests and game data both say copies of the same effect add together rather than multiply; see the Damage maths tab.
Reroll for lists effects this unique can roll on its random slots that suit its build, with the best random value. At Blacksmith level 3 you can reroll a unique's random effect with Echo Shards (1 shard rising to 20), and once you've rerolled one effect the others are locked. The fixed effect never changes.
Also as rolls lists effects the build wants that this unique can't roll, and which gear can roll them. Any of those can come from a common or rare item rerolled with shards, not only from another unique.
Fixed vs rolled compares the unique's fixed effect with the best random roll. In 15 cases a top roll matches it, so the unique isn't the only way to get that bonus.

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Groups of uniques with exactly the same fixed effect. Both the creator tests and the game data say copies of the same effect add together (two +25% give +50%), so equipping two is worth half as much as adding a bonus of a different kind. A quick in-game check on any one group confirms it for all of them.

Effect	What it does	Uniques that have it

How effect pools work

Each item belongs to one or more archetypes (Fighter, Mage, Ranger, Summoner, Support, Tank, Trickster), and its random effects come only from those archetypes' pools.
Weapons also roll from 6 effects any weapon can get. Artifacts also roll from 8 any artifact can get. Looter, Luck, Prospector and Raider can roll on all gear. Elemental armour sets (fire, frost, poison, lightning) add the other elements' damage bonuses.
Random slots by rarity: Common 0, Rare 1, Special 2, Unique 1 plus its fixed effect. Soul Storm drops add one more random slot: Rare 2, Special 3, Unique 2 plus fixed. Most items top out at 3 effects (4 is the cap).
Every slot, including the Soul Storm one, rolls from the item's own pool. The game filters out effect families the item already has, so the same effect almost certainly can't roll twice on one item. The same effect on two different items still adds together.
Echo Shards level up the Blacksmith. Rerolls unlock for Rare items at level 1, Special at 2 and Unique at 3. You reroll one chosen effect, and once you've picked it the item's other effects are locked. Cost starts at 1 shard and rises with each reroll to 20. Shard upgrades take gear to level 149; levels 150–152 only come from drops.

Effect	Best random roll	Fixed on a unique	Rolls on	Uniques with it fixed

What this means for builds

Spread bonuses across kinds. Bonuses of the same kind add, and different kinds multiply. Three +30% bonuses of one kind give ×1.9; one in each of three kinds gives ×2.2.
The crit core is Fighter's Flute plus Warrior Drums. Every hit crits at ×3.5 instead of ×1.5. Add Battle Banner's Strength for ×2 on top.
Fast-hitting weapons gain most from flat damage and on-hit effects. Grindstone's flat bonus goes on every hit before multipliers, so a weapon that hits twice as often gets it twice as often.
The best weapon rolls in The Dungeon Fish's sheet are Bully, Sharpness and Critical Edge, one from each kind.
Duplicates of the same effect add, so the Stack tests tab mostly answers itself: two of the same effect give the sum, not a multiplier.

Rule	In-game tests (creator videos)	Game data (dungeons2wiki, build 1.1.1.0)	Status
Same kind of bonus adds	+45% and +30% crit damage gave +75%.	Two +30% Sharpness give ×1.6, not ×1.69.	Tests and data agree
Different kinds multiply	Wounded × crit, Finesse × Sharpness and Duelist × Sharpness all multiplied (165 → 181 with a +10% roll, as predicted).	Separate bonus types are separate multipliers, with a warning not to assume every tooltip bonus multiplies.	Tests and data agree
Crits deal ×1.5	Crit hits did ×1.5.	Player crit multiplier is 1.5 (the class default of 2 is overridden).	Tests and data agree
Strength status doubles damage	Battle Banner and Awesomeaxe's Strength gave ×2; crit plus Strength gave exactly ×3.	Strengthened adds +1 to the base damage multiplier.	Tests and data agree
Warrior Drums: ×2.33, not ×2	Tested at ×2.33 with crits.	Adds +2 to the crit multiplier: 1.5 → 3.5, which is ×2.33 on a crit. Two drums don't stack; reapplying only refreshes.	Tests and data agree
Fighter's Flute: every hit crits	Every hit crit while active.	Sets crit chance to 100%.	Tests and data agree
Grindstone adds flat damage before multipliers	About +121 per hit at weapon level 101 and +170 at about 150. Upgrading the Grindstone didn't change it. Strength and crits multiply it. Finicky: needs time to apply and can break when another artifact is used.	Adds a flat +15 internal units to base damage, before multipliers.	Tests and data agree
Shocked or Zapped enemies take +25%	Lightning Surge's shock made enemies take 25% more.	Zapped is 1.25 on incoming damage; with Weakened (1.5) it adds to 1.75, not 1.875.	Tests and data agree
Critical Edge and the Strength effect	Both are crit damage and added together (+45% and +30% gave +75%).	Critical Edge raises the general crit multiplier and Strength raises the melee crit multiplier; melee crits use general × melee, so they should multiply.	Sources disagree
Waves (Lightning Surge and others)	Deal 90% of the hit that triggered them. Strength, Sharpness and Wounded boost them; crits and Finesse don't. Bully boosted them more than expected.	Not covered.	Tested only
Bonuses on other gear apply to melee	A crit damage roll on a crossbow raised melee hits from 189 to 214. Anything not worded as ranged-only counts.	Not covered.	Tested only
Prime Enchanter's Gauntlets' elements	Each hit lands as two elemental hits. The Dungeon Fish's sheet calls elemental bonuses "not efficient" on them; the 215k one-shot build stacks Electromancer and Cryomancer everywhere.	DungeonsDB: each element bonus boosts only half of the jump hit. Mobalytics: unique Gauntlets have about 40% less base damage than normal ones.	Sources disagree
Calculated vs real damage	A Clobberer build calculated at about 15,000 hit about 8,000. Some crits didn't apply with many effects active.	Lists activation timing, procs and multi-target cases as unresolved.	Tested only
Soul Storm generators take less damage	About 4,000 on generators vs 6,000–8,000 on mobs; maybe they can't get negative statuses, which cancels shock and Bully.	Not covered.	Tested only