Laravel 5 Class 'form' not found

This may not be the answer you're looking for, but I'd recommend using the now community maintained repository Laravel Collective Forms & HTML as the main repositories have been deprecated.

Laravel Collective is in the process of updating their website. You may view the documentation on GitHub if needed.

Form isn't included in laravel 5.0 as it was on 4.0, steps to include it:

Begin by installing laravelcollective/html package through Composer. Edit your project's composer.json file to require:

"require": {
    "laravelcollective/html": "~5.0"
}

Next, update composer from the Terminal:

composer update

---

Next, add your new provider to the providers array of config/app.php:

'providers' => [
  // ...
  'Collective\Html\HtmlServiceProvider',
  // ...
],

---

Finally, add two class aliases to the aliases array of config/app.php:

'aliases' => [
// ...
  'Form' => 'Collective\Html\FormFacade',
  'Html' => 'Collective\Html\HtmlFacade',
// ...
],

---

At this point, Form should be working

Source

---

Update Laravel 5.8 (2019-04-05):

In Laravel 5.8, the providers in the config/app.php can be declared as:

Collective\Html\HtmlServiceProvider::class,

instead of:

'Collective\Html\HtmlServiceProvider',

This notation is the same for the aliases.