I would recommend the Battlefield series from EAsy. They are BFP4F and BFH, tons of cheats, unfortunately full of cheaters too.
Then there is the League of Legends where you can buy cheats which are untraceable. The game itself is free.
Need for Speed World as it has been said above. However, notice that cheaters are getting banned there, even if it happens rarely.
Try DayZ too but the have in mind that the cheats work for now. The company has announced that they are willing to create a hack-free game. The game is not free.
Team Fortress 2 has cheats too.
And finally, you could try Rust. Full of cheats, full of cheaters
Apart DayZ, all the others are free, multiplayer, they are good games in total, they have active communities, many players and full servers for at least 18 hours a day and i personally do not expect the companies behind these games to make them hack-free any time soon.
Oh, last but not least, cheaters get tons of rage so expect to get thousands of swears in just the first few months in these games.