A jewellery company, https://www.instagram.com/michaelyoungjewels/ has two tiaras it has displayed on its Instagram page, which it asserts were owned by the Empress Elisabeth and the Greek Royal Family (the owner of the company states this in the comments section in response to a query). I make no comment on the accuracy of what is asserted but they are both pretty tiaras, especially the tiara identified as having belonged to the Greek Royal Family.

Greece - I like this tiara an awful lot.

https://www.instagram.com/p/BCr4UGTJcgF/

Austria - I find this tiara pretty but a bit underwhelming for it to belong to an Empress and therefore struggle to believe it was owned by Empress Elisabeth.

https://www.instagram.com/p/4OzhbRJcqJ/