Вьюшка ===============================

<div class="col-5 mt-5">
    <form action="{{route('pgztool.create_new')}}" method="POST">
        @csrf
        @if($dataForSelect)
        <label for="users">Выбрать проект</label>
        <select class="form-control color_label" name="project_id" id="project" onchange="check()">
            <option default="project" value="false">Выберите проект</option>
            @foreach($dataForSelect as $value)
            <option value="{{ $value['id'] }}">{{$value['title']}}</option>
            @endforeach
        </select>
        <br>
        <label for="users">Выбрать инструмент</label>
        <select class="form-control" name="tool" id="tools" disabled onchange="check_tools()">
            @foreach($dataForSelect as $tools)
            @foreach($tools['available_tools'] as $availableTool)
            <option value="{{$availableTool}}">{{$availableTool}}</option>
            @endforeach
            @endforeach
        </select>
        <button type="submit" class="btn btn-warning mt-4">Создать</button>
        @else
        <p class="bg-warning mt-3 tools_message">Выпадающие списки будут доступны после создания хотя бы одного проекта!</p>
        @endif
    </form>
</div>

То что приходит с контроллера ========================

array:2 [▼
  1 => array:3 [▼
    "id" => 1
    "title" => "Test project"
    "available_tools" => array:4 [▼
      0 => "App\Models\AdministrativeBudgetTool"
      1 => "App\Models\ContractPaymentRegisterTool"
      2 => "App\Models\PaymentReportTool"
      4 => "App\Models\PgzTool"
    ]
  ]
  2 => array:3 [▼
    "id" => 2
    "title" => "Project 2"
    "available_tools" => array:5 [▼
      0 => "App\Models\AdministrativeBudgetTool"
      1 => "App\Models\ContractPaymentRegisterTool"
      2 => "App\Models\PaymentReportTool"
      3 => "App\Models\RegisterOfContractsTool"
      4 => "App\Models\PgzTool"
    ]
  ]
]