I started keeping a spreadsheet of my collection as a backup since I was tracking orders and preorders this way. One thing I started doing while logging them is adding a 1-5 with .5 increments rating for the casting and 1-5 for the deco of the specific car along with an overall average of the two scores.

I would like to see this in the app with the ability to then filter and sort by the ratings or either casting, deco, or overall and see what the community thinks. It would be an interesting way to discover cars you may have overlooked since it is rare, at least here, to see every car in person. It could also lead you to find other people to follow who share the same taste as you.