Welcome to Android Central! Are all of your accounts saved to your Google Contacts, or are they associated with the Phone account? If the former, you can access them all by simply going to Google Contacts on the web, since they sync immediately. If they are associated with the Phone account, then you can't access them, because that account is only local on the phone, and doesn't sync with anything (unless you use HTC Sync Manager to sync them with your computer). Photos are only accessible if you were backing them up to your Google+ Photos in the cloud, or some other cloud storage like Dropbox.
Take this opportunity right now to
change your Google password. If your phone didn't have a screenlock, whoever has it now could easily access a lot of your information from your Google account. If you change the password now, it would immediately lock that person out. They could still access files on the phone, but nothing in your account in the cloud. Also, use Android Device Manager to see if you can locate the phone, and possible send a Wipe Data command:
https://support.google.com/accounts/answer/3265955?hl=en