I assume that you are already familiar with stablecoins like Tether,so there's no point of asking your question.
There are 5 popular stablecoins,nobody is going to reveal to you a secret super stablecoin that has 0 price fluctuations.
Such stablecoin doesn't exist.
If you are so afraid of price volatility,then why you are trading and HODLing cryptocurrencies,especially Bitcoin?The skilled crypto trader/HODLer should not be afraid of any price fluctuations and should not let his emotions take control over his trading and investment decisions.