In theory, the Fed can take any paper you have, including a used bus ticket, and “loan” you money for as long as they want, at whatever interest rate they want, including zero.
In theory, yes, in practice, they do that with “good” paper e.g. U.S. treasures, except in an emergency. If I’m not mistaken, they were doing repos with subprime MBS for a brief while in August, but they are not doing that any more.
