I didnt find it but is it possible to run at night all pages so the next morning the whole website is cached? Or are there other plugins who does this job? I hope someone can help me! Thanks!
Plugins such as WP Super Cache have a setting for that. It's called "pre-load", it allows you to pre-load pages and you can set an specific interval to regenerate cache.
If you publish at least 3 or 4 times a week a good configuration could be every 4000 minutes.