The best trinket for Ret Paladins at the moment is [Tiny Abomination in a Jar]. The reason being is that motes stack up very quickly for Retribution Paladins. We can proc up to 4 motes in one swing with our various attacks and abilities. On top of that, the bonus 50% damage from 8 motes procs our seals as well.
Tiny Abomination in a Jar (TAiaJ) is so powerful for us, that the heroic and normal versions are numbers 1 and 2 on our best trinkets list. If you are lucky enough to get this to drop from Putricide, it’s a must-equip!