The Fed gets regular audits as far as I can tell. But perhaps Ron Paul was campaigning for more thorough ones? (Or it was just a good sound bite?)

https://www.econlib.org/archives/2009/07/audit_the_fed_o.htm... and https://www.csmonitor.com/Commentary/Opinion/2009/0803/p09s0... might be interesting.

You might also like https://www.alt-m.org/2020/03/30/when-the-fed-tried-to-save-...