How do we create a new Eloquent Collection in Laravel 4, without using Query Builder?
There is a newCollection() method which can be overridden by that
In Laravel 5 and Laravel 6 you can resolve the Illuminate\Database\Eloquent\Collection class out of the service container and then add models into it.
$eloquentCollection = resolve(Illuminate\Database\Eloquent\Collection::class);
// or app(Illuminate\Support\Collection::class). Whatever you prefer, app() and resolve() do the same thing.
$eloquentCollection->push(User::first());
For more information about understanding resolving objects out of the service container in laravel take a look here: https://laravel.com/docs/5.7/container#resolving