Madrugada
Since: Jan, 2001
Total posts: 2

Series Minus Series Core has only a very small number of examples listed. Among the few examples:
In short, there are just way too few examples of this for it to be tropeworthy in my opinion. The only inbounds are "see also" links and one on an Analysis of Johnny Test.
tl;dr: There's no "meat" to this trope, and it's too obscure to be a thing. Garfield Minus Garfield covers the entire territory.