Is there a way to access/see all files stored in iCloud to one account?
Solution 1:
All of your iCloud Drive content will be shown here: https://www.icloud.com/#iclouddrive.
However, 1Password does not store data in iCloud Drive: it stores your passwords (encrypted) in iCloud Documents and Data, which is a separate part of iCloud.
To access your Documents and Data, on an iOS device: open the Settings app, go to iCloud, tap Storage, and tap Manage Storage.
You'll see a section called Documents and Data under the Backups section if you do indeed have documents and data stored in iCloud. You can edit/delete the data of each app here.