There exist different types of currencies and resources. You will find lists below for a better overview.

Currencies

IconCurrencyPurpose
GoldGold is a widespread and frequently used currency – can be found in stages, shops, towers and dungeons etc.
CrystalsCrystals are rare and a valuable currency, used to purchase valuable items from shops and the black market - can be found in stages, shop and dungeons etc.
Thirst for Adventure (Beer)Thirst for Adventure is used to start epic adventures. Generates automatically over time.
KeysKeys are used to access dungeons - can be found in stages and shops etc.
ArtifactCan be traded in the Dungeon Shop - found in dungeons etc.
Ancient ArtifactValuable resource found in dungeons. Can be traded in the Dungeon Shop.
Crystalized SoulThese valuable objects are created in the depths of the Magic Toilet when duplicates of heroes appear. Can be exchanged at the Trader.
Rare Crystalized SoulThese valuable objects are created in the depths of the Magic Toilet when duplicates of rare heroes appear. Can be exchanged at the Trader.
Golden HourglassThese magical hourglasses can be used to instantly finish a stage that has already been completed on the selected difficulty.
Crimson HourglassThese magical hourglasses can be used to instantly finish a dungeon that has already been completed on the selected difficulty.
Arena TicketAllows access to the arena. Generates automatically each day.
  Arena TokenCan be earned in the Arena to be traded in for valuable prizes in the Arena Shop.
Guild TokenCan be earned through guild quests and can be traded for valuable prizes in the Guild Shop.
Guild Medals

Can be earned through guild quests and are the experience points used to increase the guild level. The higher the guild level, the more bonuses are unlocked for the guild.

Types of Souls

IconTypePurpose
SoulUsed for regular banners to draw new units – can be found in stages, shops and dungeons etc.
Shimmering SoulUsed for event banners to draw new units – can be found in stages, shops and dungeons.

Upgrade Materials

IconUpgrade MaterialsPurpose
Uncommon Ascension OrbUsed to let uncommon heroes ascend in the Chapel.
Rare Ascension OrbUsed to let rare heroes ascend in the Chapel.
Epic Ascension OrbUsed to let epic heroes ascend in the Chapel.
Legendary Ascension OrbUsed to let legendary heroes ascend in the Chapel.
Weapon DustWeapon dust obtained by dismantling equipment. Can be used to upgrade equipment at the Smith.
CinderIncreases the maximum number of times equipment can be upgraded at the Smith.
EssenceUsed to upgrade heroes – can be found in stages, shop, towers and dungeons etc.
Fire ShardUsed to upgrade fire heroes to tier 1 (max level 10-20) – can be found in stages, shop, towers and dungeons etc.
Fire CrystalUsed to upgrade fire heroes to tier 2 (max level 20-30) – can be found in stages, shop, towers and dungeons etc.
Fire CoreUsed to upgrade fire heroes to tier 3 (max level 30-40) – can be found in stages, shop, towers and dungeons etc.
Nature ShardUsed to upgrade nature heroes to tier 1 (max level 10-20) – can be found in stages, shop, towers and dungeons etc.
Nature CrystalUsed to upgrade nature heroes to tier 2 (max level 20-30) – can be found in stages, shop, towers and dungeons etc.
Nature CoreUsed to upgrade nature heroes to tier 3 (max level 30-40) – can be found in stages, shop, towers and dungeons etc.
Water ShardUsed to upgrade water heroes to tier 1 (max level 10-20) – can be found in stages, shop, towers and dungeons etc.
Water CrystalUsed to upgrade water heroes to tier 2 (max level 20-30) – can be found in stages, shop, towers and dungeons etc.
Water CoreUsed to upgrade water heroes to tier 3 (max level 30-40) – can be found in stages, shop, towers and dungeons etc.
Light ShardUsed to upgrade light heroes to tier 1 (max level 10-20) – can be found in stages, shop, towers and dungeons etc.
Light CrystalUsed to upgrade light heroes to tier 2 (max level 20-30) – can be found in stages, shop, towers and dungeons etc.
Light CoreUsed to upgrade light heroes to tier 3 (max level 30-40) – can be found in stages, shop, towers and dungeons etc.
Shadow ShardUsed to upgrade shadow heroes to tier 1 (max level 10-20) – can be found in stages, shop, towers and dungeons etc.
Shadow CrystalUsed to upgrade shadow heroes to tier 2 (max level 20-30) – can be found in stages, shop, towers and dungeons etc.
Shadow CoreUsed to upgrade shadow heroes to tier 3 (max level 30-40) – can be found in stages, shop, towers and dungeons etc.
Uncommon MaterialThis material can be used to upgrade equipment - acquired by dismantling uncommon or higher equipment.
Rare MaterialThis material can be used to upgrade equipment - acquired by disassembling rare or higher equipment. 
Epic MaterialThis material can be used to upgrade equipment - acquired by disassembling epic or higher equipment.
Legendary MaterialThis material can be used to upgrade equipment - acquired by disassembling legendary equipment.
Reincarnation StoneThese mystical stones can be used in the Chapel to reset a hero and get all resources back that have been invested into it.
Skill Tome (uncommon)The teachings in this ancient book can be used to upgrade the skills of uncommon heroes.
Skill Tome (rare)The teachings in this ancient book can be used to upgrade the skills of rare heroes.
Skill Tome (epic)The teachings in this ancient book can be used to upgrade the skills of epic heroes.
Skill Tome (legendary)The teachings in this ancient book can be used to upgrade the skills of legendary heroes.