There's a decentralized peg to USD called DAI which is backed by ETH as collateral. It's maintained the 1$ USD peg throughout the entire crypto bear market. MakerDAO is quite impressive, and I hope to see it absorb the liquidity away from tether.
For example, if I ever see DAI trading at, say, $1.02 then I would quickly mint some new DAI and sell for USD. Likewise, if DAI is at $0.98 then I would buy it back, then burn what I've minted, collecting a profit.
Also note that with traditional USD pegs, they are not always on parity and hover a few cents from time to time. For example the HKD. https://en.m.wikipedia.org/wiki/Hong_Kong_dollar
In essence, if you declare a plausible intent of keeping a rate near 1$ by accepting limitless orders to buy it at 0.98$ and sell it at 1.02$, and can keep that promise, then that's a decent peg.