With Krystal, you can add watch-only wallets to view the tokens as well as transactions associated with them. However, you cannot do any transactions with the wallets. 

Go to the “Settings” tab and select “Manage Wallets 

Click on the “Watch” button on the top right of the screen and click “Add watched wallet

Fill in the wallet address (public key) or the ENS domain. You can make it easier to recognize by adding a label to the wallet.