This app was mentioned in 5 comments, with an average of 1.60 upvotes
I use an app called My Collection for Android. Works great, if you're still looking.
https://play.google.com/store/apps/details?id=com.tuyware.mycollection.dimensions
The app dev had already made this as a separate app:
https://play.google.com/store/apps/details?id=com.tuyware.mycollection.dimensions
I've been using this app, is it kinda what you're after? https://play.google.com/store/apps/details?id=com.tuyware.mycollection.dimensions
There's also versions for iOS: https://itunes.apple.com/us/app/my-collections-dimensions/id1186912046 And Windows: https://www.microsoft.com/en-us/store/p/my-collections-dimensions-ed/9n6mc2281rxf
If you just want the building instructions you could use 'My Collections Dimensions Ed.'. It has the building instructions for all figures/vehicles/gadgets
Android: https://play.google.com/store/apps/details?id=com.tuyware.mycollection.dimensions
iOS: https://itunes.apple.com/us/app/my-collections-dimensions/id1186912046
Windows (Phone): https://www.microsoft.com/en-us/store/p/my-collections-dimensions-ed/9n6mc2281rxf