Issue: After installing ScottPlot via PackageManager the UserControl "WpfPlot" does not appear in the Toolbox (VS 2019).

I found two solutions that might be mentioned in the Quickstart document to make life easier for a beginner:

Solution 1: Add Control manually in the XAML editor without adding the UserControl to the Toolbox:
<Grid> <scottplot:WpfPlot Name="wpfPlot1" Margin="10"/> ... </Grid>

Solution 2: Right-click the Toolbox, pick "Choose Items...", click "Browse" in any tab, find the ScottPlot.dll, select it and click "Open".

In both cases you have to add in the window tag:
xmlns:scottplot="clr-namespace:ScottPlot;assembly=ScottPlot"