The following features of an Amazon S3 bucket can only be suspended once they have been enabled:

1. Versioning: Once versioning is enabled for an S3 bucket, it cannot be suspended. However, you can delete individual versions of objects or delete all versions of an object (excluding the current version of the object) to effectively remove versioning for those objects.
2. Static website hosting: If you have enabled static website hosting for your S3 bucket, you cannot suspend it. However, you can disable static website hosting by deleting the appropriate bucket policy.
3. Event notifications: If you have enabled event notifications for your S3 bucket, you cannot suspend them. However, you can delete individual event notifications or the entire event notification configuration to effectively disable event notifications for the bucket.
4. Object tagging: Once object tagging has been enabled for an S3 bucket, it cannot be suspended. However, you can delete individual tags or the entire tag set for an object to effectively remove object tagging for that object.
5. Requester pays: Once requester pays is enabled for an S3 bucket, it cannot be suspended. However, you can disable requester pays by removing the bucket policy that enables it.
6. Server access logging: If you have enabled server access logging for your S3 bucket, you cannot suspend it. However, you can stop logging by deleting the appropriate bucket policy or by deleting the access log objects from the bucket.