Obviously holocrons and written texts from Jedi Masters are much sought after by the Empire and other parties. But what about things that aren't so influential to PCs?

My party has expressed interest in having a mission where they raid an old Jedi temple to gather some "relics" that they can sell to collectors. While laying out the actual crypt of a long-forgotten master isn't the hard part, what I'm having trouble coming up with is the McGuffin they find. Is it a statue? Maybe a piece of jewelry? I cannot for the life of me figure out what would be worth finding in the basement of a long destroyed temple that isn't a holocron, book or crystal. Any thoughts?

Check out Nexus of Power. It has some great modular encounters that would fit the bill nicely.

Depends on the collector and what they want. Maybe old Jedi training gear is enough to spark their fancy? Think old robes, training lightsabers, Temple guard armor, pretty much anything from the equipment section of a F&D career book. Then, from the Prequels, think about stuff that was in the background of Jedi Temple scenes, like busts of Jedi masters, Yoda's chair, etc. It would totally depend on what this collector is looking for and could be quite mundane.

Given Palpatine's efforts to rewrite history, mundane texts and computer cores with basic history of the Order would be valuable as well. The Jedi did have some of the more complete archives around.