There isn't a fixed number of accounts or Pages that is considered "safe." Facebook evaluates many factors such as account authenticity, behavior patterns, content quality, and compliance with its policies.
For long-term stability, it's generally better to focus on building and warming up a small number of genuine accounts rather than creating large numbers of accounts. If you're scaling organic marketing, make sure each account represents a real person or business and follows Facebook's Terms of Service.
As for Pages, one account can manage multiple Pages, but quality and compliance matter far more than quantity.