If you weren’t already prepared (see other comments) then assume every credit/debit card you had saved in your Google Wallet/Apple Pay has been stolen - That’s one reason people snatch phones while unlocked and try to keep it unlocked.

Also assume any payment apps you have installed are now compromised e.g. Venmo and similar - that’s another reason people steal unlocked phones and try to keep it unlocked.

The above assumes you did not have any additional passwords/locking in the apps themselves beyond the phone’s screen unlock - I purposely

You may be able to remote lock the phone after the fact if you get to a computer or a someone you know with a phone on them to get online and initiate a remote lock.