There's one on Scribblehub, but the guy quickly found a substitute body (an ancient snake or whatever) and then the author disappeared.
Gamers of the Underworld - https://www.novelupdates.com/series/gamers-of-the-underworld/ - Webnovel is uploading this novel. Just find any aggregator site available to read it on.
The boss behind the game - https://www.novelupdates.com/series/the-boss-behind-the-game/ - Same as previous post, Webnovel is hosting this novel, find any aggregator site to read it on.
i reincarnated as sword : the mc not system but sword hm we can said that godly sword in the ruin then one day a girl ( loner ) come and they traveling together. bassically mc help that little girl reborn as system : i dont know this one
大杀戮系统 / The Great Killing System One of the best novel systems in my opinion, he also made an organization called "Underworld" MC a cruel man, careful of his enemies. Almost no romance because the MC focuses on taking care of the organization's enemies or making chaos, Usually chaos is created when there is a mission from the system. Too bad no one has translated it yet, I hope someone will. Raw can be searched on google.
Hosted in sufficient velocity is: https://forums.sufficientvelocity.com/threads/broken-adventure.53999/ which features a multidimensional entity turned mortal developing and becoming a system like entity for others. It has a spin-off that’s more recent that involves a fragment of himself becoming a system here: https://forums.sufficientvelocity.com/threads/broken-adventure.53999/ as a note, the focus is more on the system users when it’s available.
Try "The God Virus" mc is a AI that was called Virus bcuz it wage war to humans he/she also has all knowledge about past,present,future and also know everything about cultivation,magic, and technology, means that he/she is so op And he/she try to time travel bcuz of boredom
The Legendary Mechanic, mc becomes an npc but there are still players, he has quests and Spoiler can give out quest to the players which means that he is also part of the system somehow? One thing is for sure that mc is hilarious even though sometimes he can be too op but that can be negligible.
Game of the world tree Its completed I dont think its fully translated tho Mc isnt the system system but pretty much designs it so similar I guess