With the launch of the structure deck shaddoll showdown in 2020. This engine has revolutionized fusion decks.
Below you can see versions of shaddoll in TCG.
Deck Shaddoll Showdown
Version Shaddoll Invoked
Version Shaddoll Lightsworn
It is a unique deck, where most of its monsters are darkness in addition to turning on effects in the graveyard, a deck of mergers and finally it does not have negations (Except the version with invoked) So it’s easy to side deck for your opponent.