As others have already stated, probably the ideal attachment would be a Push/Pull or Slipsheet attachment.

Would be worth contacting a supplier to enquire iof the attachemnt would be suitable for your use as this type of attachment is normally designed for pulling and pushing products from/into containers and then onto pallets provided a slipsheet is available under the product.

It might work for the metal plates but I guess it depends on how you get the metal plate onto the slipsheet attachment first.