Which fields are automatically indexed in Salesforce?

Fields that are automatically indexed in Salesforce are:
-RecordTypeId.
-Division.
–CreatedDate.
-Systemmodstamp (LastModifiedDate)
-Name.
-Email (for contacts and leads)
-Foreign key relationships (lookups and master-detail)
-The unique Salesforce record ID, which is the primary key for each object.

The following fields are indexed by default: primary keys (Id, Name and Owner fields), foreign keys (lookup or master-detail relationship fields), audit dates (such as LastModifiedDate), and custom fields marked as External ID or Unique.