Game trainers are a type of software that modifies the game code to give the player an advantage over other players. They are often used to cheat, giving the player infinite health, ammunition, or money.
Kiddion's Modest Menu
One of the best free mod menus for Grand Theft Auto V.
The one and only Rocket League trainer with a ton of features.
One of the first mod menu trainers for GTA 5.
The most popular GTA 5 mod menu ever released.