Is there one? I want a bard for a non-magical continuity. What if I replaced the spells with the warriors weapon group abilities or the Gunslingers grit? Would that be OP?
I think the OP wants to preserve the bardic performance ability, or am I wrong? To me, that is what puts the bard in bard. I could imagine a non-magical bard that replaces spells with some investigator abilities, and perhaps more bardic performance rounds and the ability to maintain more than one bardic performance at once at higher levels.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.