Shortening list of arguments to some kind of a variadic function
This will depend on whether or not all of the indicators you're interested in passing have the same generic type arguments. If they do then iSR5's solution is the simplest.
If not then you'll need a more complicated solution. On one hand I notice that you're not using any of the outputs of ComputeNextValue; you're only providing inputs to the indicators. Then one possible solution would be to define an interface with the void counterpart of ComputeNextValue which only takes an input and produces no output:
public abstract class IndicatorBase&lt;TInput, TOutput&gt; : IIndicatorBase&lt;TInput&gt;
    where TInput : struct
    where TOutput : struct
{
    public abstract TOutput ComputeNextValue(TInput input);
    public abstract void Reset();

    void IIndicatorBase&lt;TInput&gt;.ComputeNextValue(TInput input) =&gt;
         ((IndicatorBase&lt;TInput, TOutput&gt;)this).ComputeNextValue(input);
}

public interface IIndicatorBase&lt;TInput&gt;
    where TInput: struct
{
    void ComputeNextValue(TInput input);
}

Then ImportAndPreload can become this: (I'm not sure what BinanceKline is, but the input type you're supplying to each indicator is the type of BinanceKline.Close, so that'd be the generic type argument for IIndicatorBase)
private void ImportAndPreload(string symbol, KlineInterval interval, params IIndicatorBase&lt;TypeOfBinanceKlineDotClose&gt;[] indicators)
{
    ...

    // Preload indicators
    for (int i = 0; i &lt; candles.Count; i++)
    {
        foreach (var indicator in indicators)
        {
            indicator.ComputeNextValue(candles[i].Close);
        }
    }
}

...

ImportAndPreload(symbol, interval, macd, stoch, rsi, ema);

This will support any indicator whose input is the type of BinanceKline.Close.