I'd say Firlefanz and bars of gold are great items, also you can't go wrong with old fashioned blood herbs.
To make trophies (or any item) shine brighter, place below them a sun catcher and maybe a lit torch (you can get as many as you want for free from Grimvale Quest, just ask for "lit torch" every time you talk to NPC "Rhargu", no need to make it sparkling).
The only thing you need to find items big enough to hide sun catchers/lit torches so that they're not visible: a suggestion would be most tapestries or even snowballs I believe