When I play D&D I at times try to spare enemies I fight because I don't believe in going ham on a few poor thieves that are just trying to get by by robbing me, or killing a guy I had a disagreement and a few thrown out curse words with. I haven't gotten far enough into the story to really find an option for it yet but is there an option to not kill enemies and instead just knock them out after a fight? If not I think it should be added. I think it would lead into interesting dialogues or maybe different quest lines, such as a mad woman running up to you and because you knocked her out you realize she was being mind controlled by an evil wizard just nearby.
It's something small but I think it would add a bit more to my characters personally because I always try to be a "goody two-shoes" when I play D&D.
This would be compatible with 5e rules and I agree should be an option. We should not be forced into being murder-hobos.
Knocking a Creature Out
Sometimes an attacker wants to incapacitate a foe,
rather than deal a killing blow. When an attacker
reduces a creature to 0 hit points with a melee attack,
the attacker can knock the creature out. The attacker
can make this choice the instant the damage is dealt.
The creature falls unconscious and is stable.
If they were creative, they could even re-purpose many of the "Speak With Dead" options we might have and offer an "Interrogate" option after subduing an enemy in this way.
The truth is that subduing and interrogating enemies is a far more common "thing" in D&D than killing and speaking with dead when you want to get some additional information out of an antagonist.