How can we know what are all attributes can be secured in CRM with field level security?

There are thousands of attributes from all entities those can secured with field level security. We can get those attributes in two ways: • Install metadata browser for the customized CRM and query the entity metadata for the following properties CanBeSecuredForCreate, CanBeSecuredForRead, CanBeSecuredForUpdate • Open EntityMetadata.xslx file for uncustomized CRM and query the entity metadata for the following properties CanBeSecuredForCreate, CanBeSecuredForRead, CanBeSecuredForUpdate