I would be thrilled to see Queen Silvia wearing Queen Victoria of Sweden's pearl and diamond corsage brooch, as it has been very rarely seen (there are only a few pictures of Queen Victoria wearing it, and Queen Silvia has worn it only once, on 6th October 2016, for a State dinner at Charlottenburg Palace in Berlin - and no other Queen or Princess inbetween).



Queen Victoria wearing the same brooch in the middle of her corsage:



Due to the brooch's "spiky" aspect, I think it would make a great match with Queen Sofia of Sweden's diamond tiara.
The tiara and corsage brooch could be matched with Queen Victoria's wedding-gift sapphire, pearl and diamond necklace (and a blue dress), and the jewel combo would be perfect!



For the Nobel "day after" dinner at Stockholm Royal Palace, I would love to see Queen Silvia with the Connaught Aquamarine Kokoshnik (Princesses Victoria, Sofia, Madeleine and Christina have worn it, but not Queen Silvia so far, if I remember correctly). And/or the Connaught Scarab Necklace, which Princess Lilian bequeathed to Queen Silvia, but I don't remember of the latter wearing it.