That's a dirty 20 on perception!
Sorry it took so long to get to this.
So! Obviously there are several maps, all showing a variety of locations and all varying states of completeness quality. I don't know how interested Garnet would be in those, but there are some that show certain parts of the Outlands, which could potentially be useful for her travels. Again, not sure if she'd be interested, but they're there. There's also some guidebooks to a variety of planes and places within those said planes.
Aside from that there are also several sets of cartographer's tools, all also in varying states. You get the feeling that whoever works here probably goes through a lot of them.
There are also some compasses - some that Garnet, being raised by dwarves, have quirks typical of dwarven craftmenship, as well as some letters in dwarven engraved onto them - and also a variety of little knick-knacks and trinkets that whoever works here may have collected from their travels, all likely from different planes.