Keltner channel indicator with a multiplier and two ways to calculate the boundaries:

     By averaging the candle body size
     Averaging the ATR indicator data

The Keltner channel can be used as an independent indicator, but also as a source of initial data. An example is the "Squeeze Momentum Indicator" published on tradingview.com with the most likes. The translation of "Squeeze Momentum Indicator" from Pine to MQL 5 was done by me.