This is a update of @APShredder's original 'BlendModes Plus' plugin. See changelog below.
Effects -> Tools -> BlendModes Plus
v3.1 (July 14, 2019)
Changed: The handling of the Clipboard is now done by a Paint.NET helper function.
Fixed: In some situations the 'Fit' Image Position would not work correctly.
v3.0 (Sept 8, 2018)
Changed: Now uses