Looking for more stories with a System suddenly being instituted on Earth
Zethuron Wrote: The Scourged Earth is one, difference is that it is sci-fi instead of fantasy.
Reading it now and it's off to a great start. Thanks for the recommendation
The Oscillation has something system-like, but not a full menu-like system you'd normally find.
Kammi Kettu is similar in this, but it doesn't have an actual 'system', it just gives them their powers and instead lets them figure it out on their own, without the help of what a system would offer.
There's also Gate of Revalation which is a Chinese novel.
Legend of Randidly Ghosthound
Locking Horns, Breaking Teeth. It's the rewrite of The Minotaur Paladin.
(Warning: for the last few chapters the quality dropped and there is no ending, but what is there is still worth reading).