Improve AOSP based apps UX
We can pull a lot of LineageOS AOSP based apps like Messaging, Calculator, DocumentsUI, Contacts, Email, Gallery, DeskClock, Dialer and Camera since they have improved UX and design, or we could at least pick specific changes from them.
They are better than plain AOSP because they provide:
Proper API 28/29 updates for notifications, foreground/background services etc.
Various bug fixes since the AOSP apps are abandoned for years.
In some cases extra features that are standalone and do not depend on lineage SDK.
Uniform material design icons.
Material UI for some apps like Gallery instead of AOSP gingerbread look.