sometimes i like to think about things like items etc i'd add to a version of my setting where it's specifically some sort of video game. here's one that just popped into my head right now:
Nanite Revival Canister
A small canister of nanites. These ones are programmed to detect when the host is dying and rapidly repair any severe damage or injury. The process expends their entire energy reserve and severely deteriorates them, making the effect single-use. Experts recommend not having more than one dose of these in your bloodstream at a time, as any more could interfere with your immune response and/or any other nanite-based medications or auto-doctor systems present.