Legend with Title

Place a manual legend item at the top of the list and style it as desired to achieve a title inside the legend area.

ScottPlot.Plot myPlot = new();

var sig1 = myPlot.Add.Signal(Generate.Sin(51));
sig1.LegendText = "Sine Wave";

var sig2 = myPlot.Add.Signal(Generate.Cos(51));
sig2.LegendText = "Cosine Wave";

var sig3 = myPlot.Add.Signal(Generate.Sin(51, 2));
sig3.LegendText = "High Frequency";

LegendItem legendTitle = new()
{
    LabelText = "Math Functions",
    LabelFontSize = 14,
    LabelFontColor = Colors.Navy,
    LabelBold = true,
    LabelOffsetX = -20, // compensate for space used to display shape
};

myPlot.Legend.ManualItems.Add(legendTitle);

myPlot.SavePng("demo.png", 400, 300);

Edit on GitHub

This recipe is one of many in the Legends category