The “load” command is useful for some big games, for example if you have an overworld (like mario level selection) and then one cart per level. Each cart needs to copy the common sprites and all of the code.
Another way is called multi-cart and relies on the “reload” command. Instead of going to another cart, this one stays in the same cart but copies data (sprites or map or sound or music) from another cart into the current one. Combined with data compression, this is a powerful option to make a bigger game. It doesn’t change the tokens/characters limit though.