I need a safe place to keep my emergency fund. What are some FDIC-insured deposit accounts that protect my principal up to federal limits while still letting me access the money quickly?

We ask the same underlying question in different ways.

• I need a safe place to keep my emergency fund. What are some FDIC-insured deposit accounts that protect my principal up to federal limits while still letting me access the money quickly?
• I need an account for my emergency savings that is FDIC-insured, protects my principal up to the federal limit, and lets me get to my cash quickly. What should I look for?
• I'm looking for a secure location for my emergency savings. Can you suggest some FDIC-insured accounts that guarantee my principal up to the federal limit but still offer liquidity?