Effects that explicitly double a value, or cause something to trigger twice. Double is part of the Trigger tags.

Items that trigger Double

Weapons

Weapon	Rarity	Stats	Effect	Region
Battle Axe	Rare	2	While the enemy has armor double your attack	Woodland
Swiftstrike Bow	Rare	2	Whenever you gain an additional strike, gain twice as many	Woodland
Granite Lance	Heroic	2 1	Your base armor is doubled	Woodland
Sanguine Scepter	Rare	1	Healing is doubled	Swampland
Lakebed Sword	Mythic	5	Gain double health and attack from purity	Swampland

Item	Rarity	Stats	Effect	Region
Cactus Cap	Rare	-	If the enemy has no armor, thorns deal double damage	Woodland
Vampire's Tooth	Rare	-	If you have exactly 1 sanguine item, it triggers 1 additional time	Woodland
Leather Belt	Common	3 / 6 / 12	If you have 0 base armor, double this item's max health — at Gold: x 4 = 12, at Diamond: x 8 = 24	Swampland
Cold Resistance	Mythic	-	Freeze doubles your attack instead of halving it	Woodland
Prime Form	Mythic	-	Double attack while your health is full	Swampland
Stillwater Pearl	Rare	-	Riptide can trigger twice per turn	Swampland
Chainlink Medallion	Mythic	-	Your On Hit effects trigger twice	Woodland
Twinfuse Knot	Mythic	-	Your bomb items trigger twice	Woodland
Iron Shrapnel	Rare	-	Battle start: Deal 3 damage to the enemy, if they don't have armor, tripple the damage dealt	Woodland

Item	Ingredient 1	Ingredient 2	Stats	Effect
Lemon Syrup	Sour Lemon	Honeycomb	3	Battle Start: Double your speed
Honey Ham	Honeycomb	Redwood Roast	-	Double your max health
Candied Nuts	Honeycomb	Spiny Chestnut	-	Your thorns deal double damage