I've been half-toying with the idea of a Bard dip for a Barbarian. The spells of course would need to be mostly utility, but using Bardic Inspiration as a bonus action, Expertise for grappling and so on, and either Whispers or Swords subclass abilities for a bit of extra damage seems like there's enough potential to avoid being too sub-optimal.

The idea of a hulking Barbarian with evil vizier-like tendencies amuses me greatly.