(I honestly don't think I've played enough video games, but here goes nothing..)
Some of my favorite systems are Yandere Simulator and Undertale.
Undertale: While it is similar to some RPG battle systems, it's pretty unique, as you have the mercy option and can talk to the enemy.
Yandere Simulator: This is more of the up and coming system. Your attack time increases depending on your level of sanity. It gives a much better sense of realism and adds challenge to the game.