Pretty much just the title, within the following restrictions:
- Multiclassing approved
- 20th level
- only official material (No unearthed arcana, but anything optional material from TCoE that might effect cantrips is okay)
- All cantrips must be unique (a Cleric 1/Bard 1 knows 5 cantrips, but they must be 5 different cantrips)
- Magic items that provide a specific cantrip are okay, but no boons that can be continually stacked.
- Feats are Okay.