what about aura of hate that provide oathbreaker paladin subclass?
None of my Oathbreakers never got that far :), so I cannot comment.
But on paper a +3/4 boost to damage caused by Undead and Fiends in 3m radius does not look aweinspiring to me. Especialy as those Fiends and Undead must be produced by somebody else, the Oathbreaker gaining Animate Dead spell at lvl 9 ...