A book/movie/object collection shelf app that has barcode scan, ISBN search, and custom database entries like money spent. They were really popular in the early 2010s but mostly subscription based and Mac only. I could probably repurpose something like Calibre to do similar things but that's a bit overkill and a lot of non-book entries would take too long to setup.

I've had success with playing scary games while they watch and when it gets too much I have the characters react in silly ways. Courage the Cowardly Dog, Are you Afraid of the Dark, Goosebumps, etc. You could also try meta horror like Cabin in the Woods, Tucker and Dale. Or something with laugh breaks to defuse the tension like Army of Darkness or Monster Squad.