Special fusions ignore the normal chart. You need every ingredient at once, and many results also need a Confidant at rank 10 or story progress first.
Persona 5 Royal special fusions
All 24 special fusions in Persona 5 Royal and the exact personas each one needs.
Playing the original Persona 5? This calculator uses Royal's data. Royal added personas, two arcana (Faith and Councillor) and a new treasure, so a few results differ in the original game.