This might involve all kind of data:
- SMS/MMS messages
- contacts, calendar data (in short: all things PIM)
- apps and their data
The tag is also suitable if you want e.g. to migrate from one SDCard to another. Please keep in mind that though your question should be Android-related, your question might also deal with migrating data from a non-Android device to an Android device or vice versa.
- data-recovery: restoring lost data