I use hacker bot for mobile game mods that I use on my Blue Stacks and Nox emulators. So far I have had no problems. All the game hacks they include in their tool are from legit places, but not all of them are updated. If you want to find free mods for iOS especially, you are going to very often not be left with many options at all, Android is better. I do not known about PC games, as I do not very often play on PC, with the exception of minecraft, where I do not use any cheat apps. The wiki is also useful for learning how cheats work and what they can do.