(From a Jan/Feb 2019 Atlantic article)

The Alarming Scope of the President’s Emergency Powers

The moment the president declares a “national emergency”—a decision that is entirely within his discretion—more than 100 special provisions become available to him. While many of these tee up reasonable responses to genuine emergencies, some appear dangerously suited to a leader bent on amassing or retaining power. For instance, the president can, with the flick of his pen, activate laws allowing him to shut down many kinds of electronic communications inside the United States or freeze Americans’ bank accounts. Other powers are available even without a declaration of emergency, including laws that allow the president to deploy troops inside the country to subdue domestic unrest.

Article gives link to this guide:

https://www.brennancenter.org/our-work/research-reports/guide-emergency-powers-and-their-use

https://www.theatlantic.com/magazine/archive/2019/01/presidential-emergency-powers/576418/