1. The dollar itself was created two centuries before the US left the gold standard. "Created" being the operative word. Created by Congress because America needed its own national currency.
2. Anyone who dug some gold up in their backyard was creating money when we were on the gold standard.
3. In 1862 paper money became legal tender in the USA without any guaranteed convertibility to any metal; that remained the situation until 1879. I.e. the government simply created money.
4. On January 31, 1934, the US dollar was devalued from $20.67 per gold ounce to $34. In other words money was created by an act of Congress.
Or to sum all that up for you: at a minimum Congress has always had the power to create money. All the metallic standards ever conceived of have been arbitrarily decided and governments have always had the ability to change the standard at will to create more money.
Before 1971 dollars were backed by Gold, now they are backed by US Tbills (and some real-estate since 2008).
It's not that different.
Gold and US TBills are both valuable assets.
What the OP meant by creating money out of nothing was fiat currency, which we do have now.
If you decide to use a commodity also as money, that's fundamentally different, and econ textbooks can confirm this for you.
T-Bills are backed by fiat currency, not by a commodity.
The Fed, and also the banks through fractional reserve banking, genuinely do create "money out of nothing."
Check out A Monetary History of the US by Milton Friedman and Anna Schwarz. Here you will find a Nobel Prize winning econonist who wanted to dramatically reign in, or even end, the Fed and get rid of fractional reserve banking.
TBills just bonds. They are 'backed' by the US Governments credibility to pay back the loan.
USD is generally backed by an asset - fractional reserving not withstanding.