Full Idea
Meinongian tropism has the advantage that possible worlds might be thought of as sets of 'qualitons' and 'relatons' (quality and relational tropes).
Clarification
'Meinongian' happily talk of non-existent things
Gist of Idea
Maybe possible worlds are just sets of possible tropes
Source
John Bacon (Tropes [2008], §3)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.4
A Reaction
You are still left with 'possible' to explain, and I'm not sure that anything is explain here. If the actual world is sets of tropes, then possible worlds would also have to be, I suppose.