You can get Slaying tokens as a random reward from killing monsters.
You can get Crafter tokens as a random reward from crafting items.
Both tokens can be redeemed at 32, 62 KV inside the Market of Wonders.
There are currently 2 Slayer token rewards and 1 crafter token reward, these require 250 tokens to turn in to unlock and they are non-repeatable.
There are also repeatable quests you can turn the tokens in for fast xp!