I'd love to see some kind of native app for NodeBB forums on iOS. I only care about iOS, but I imagine an Android app would be useful too.
An app like this as I imagine it would take an approach similar to that of the Slack app. In case you're not familiar, the Slack native apps involve signing into an individual Slack channel, and then having a way to switch between them. It doesn't try to manage multiple channels at once within the app, a channel always takes up the entire screen.
I could imagine a NodeBB app that allowed users to sign into multiple forums, and switch between them. The main feature of this app that the web platform could not offer would be push notifications, whenever you receive a notification on the forum you receive a native notification on the device.
This could be a pretty simple app, but I think providing some kind of native platform on mobile devices would be beneficial.