How to export users and passwords in a SQL file

I’m getting lots of errors due to database trashes, that were increasing since the installation long time ago, and due to updates that don’t clean unused tables, etc…

I want to make a fresh install, but I needed to export the tables related to the users, and maintain only the username, password, email and avatar. Which ones should I choose? My initial idea is:

oc_users
oc_accounts
oc__groups

And what more? Can I empty oc_preferences? Will it be recreated after the first login?