When I was playing dying light with friend we discovered that every timw you go to sleep and wake up air drop will appear, if you don’t know air drops are pretty rare and if you collext them and deliver to one guy you will recieve lots of xp, we used that multiple times to unlock grapling hook very early. Air drops also gave lots of medicine which was hard to get in early game and that very helped us
Many years ago there was a BBS door game called Legend of the Red Dragon (LORD). My memory of the exact exploit is fuzzy, but the game was expandable and the sysop had installed some expansion where I could get gems early on and quite easily, which I could trade for potions that would increase my stats. This led to me having a level 1 character with no armor and a stick – basically starting gear – that was unstoppable. But instead of levelling I’d leave the character like that and all the other maxed out players couldn’t defeat me in duels, and they were all big mad and complained to the sysop.
Eventually he figured it out and I think changed the config for the expansion so that gems were not so easy to come by. But for a good few months I was at the top of the leaderboard.