You can exchange Exotic Tokens for other Exotic goods in the Exotic Token Shop. The shop becomes available when you have at least one Exotic Animal of each category.
To access the shop, tap the Merchant, then tap the Exotics button.
At the top of the Exotics screen, you will find the Exotic Token Prizes you can redeem using the Exotic Tokens you have collected. The items in the shop will reset periodically, so avail of the goods you like as soon as you can.