click the stage to change its costume to better see the effect of the shadow. from @griffpatch 's tutorial on pen effects. Might be useful to have the ground of Scratch Rainworld "pop" . The drop shadow's distance and darkness can be adjusted as well. the outline can also be changed via the brightness block to just be a darker version of the main sprite, if you want a less abrupt outline.
@griffpatch After @ItzGel mentioned that this code could be adjusted for moving sprites, I updated it and now press the arrow keys to see the moving effects. Now the outline looks like it slightly lags behind it, though. If you want to just change the brightness of the outline up for your own project, it gives it a bit of a 3D effect