Hot take: I can't stand the word "dunamancy". I don't care for critical role, so maybe it's justified somehow (or maybe just if someone I liked said it a lot I'd learn to let it go), but as it is, it hate it. It's not duna/dyna- (physical force or potential energy) it's not a -mancy (a form of divination), and it sounds like a cringelord teenager's invented name for sand magic. Plus now that it's canonized, I have to argue with every group I run for that my setting doesn't subscribe to the many-worlds theory and that is not an acceptable flavour for their magic in my game.

Anyway to answer the question, I once saw a class entirely reflavoured from top to bottom as a Chronomancer. You probably think it was a wizard or a warlock or something, but no, it was the Battle Master Fighter.

Weapon/armour proficiency and extra ASIs were because they did extra training in a personal timeloop. Second Wind was a short personal rewind, Action Surge was a personal fast-forward. Most of their maneuvers were various manipulations of time; rewinding themself to parry, slowing the enemy for precision strike, looping themself for feinting strike, rewinding an ally for rally.

I don't remember all the flavour, but god dang it was cool.