If what you want is "something that always is worth _exactly_ 1 USD then you are asking for the unatainable. As others have mentioned, it is _impossible_ in an open market to have a true 100% no variability peg. Markets work on supply and demand and the instant that one exceeds the other the peg will drift.

A good stable coin will have pressures that push that drift back toward the target, but it is impossible to stop the drift from ever occurring. The USD itself presumably targets some basket of goods, but it drifts away from that basket of goods. So even the USD isn't a "stable coin" by your definition.