I really like the AppCache manifest plugin, although it will be deprecated by the wide-spread adoption of ServiceWorkers. The AppCache manifest, however, still does a pretty decent job when you're developing a mobile app.
Regarding webpack tricks: I think, many developers don't know how to leverage file hashing correctly. If done right, the user only needs to download a small file after you've deployed a new release. If done wrong, the user needs to download all files again. For instance, you can store some information about the compilation in a webpack.records.json. With this information, webpack is able to re-use ids which prevents file hashes from being changed. @sokra has some interesting slides on this topic.