Make all your models mass assignable

It is not a recommended approach for security reasons, but it is possible.

When you want do this, you don't need to set an empty $guarded array for every model, like this:

protected $guarded = [];

You can do it from a single place, just add following line to the boot() method in your AppServiceProvider:

Model::unguard();

Now, all your models are mass assignable.

Tip given by @CatS0up