This is a sample of a custom pre-vaule editor that is a checkbox property for the grid

grid.config

[
  {
    "label": "Show by state",
    "description": "Show this row for the following states.",
    "key": "state",
    "view": "/App_Plugins/StatePicker/state-picker-list.html",
    "applyTo": "row",
    "defaultConfig": {
      "selectMultiple": true,
      "displaySelectInversed": true,
      "items": [
        {
          "text": "Arizona",
          "value": "arizona",
          "selected": false
        },
        {
          "text": "California",
          "value": "california",
          "selected": false
        },
        {
          "text": "Colorado",
          "value": "colorado",
          "selected": false
        },
        {
          "text": "New Mexico West Texas",
          "value": "new-mexico-west-texas",
          "selected": false
        }
      ]
    }
  }
]

package.manifest

{
    "gridEditors": [
        {
            "name": "States",
            "alias": "states",
            "view": "/app_plugins/StatePicker/state-picker-list.html",
            "icon": "icon-code",
            "config": {
                 "items": [
        {
          "text": "Arizona",
          "value": "arizona",
          "selected": false
        },
        {
          "text": "California",
          "value": "california",
          "selected": false
        },
        {
          "text": "Colorado",
          "value": "colorado",
          "selected": false
        },
        {
          "text": "New Mexico West Texas",
          "value": "new-mexico-west-texas",
          "selected": false
        }
      ]
            }
        }
    ],
    javascript:[
        "/app_plugins/StatePicker/state-picker.controller.js"
    ]
}

state-picker-list.html

<div ng-controller="state-picker.controller">
  <div ng-repeat="item in items"  class="checkbox" ng-class="{'displaySelectInversed': model.defaultConfig.displaySelectInversed}">
    <label>
      <input type="checkbox" value="{{item.value}}" ng-model="item.selected" ng-click="select(item)">
        {{item.text}}     
    </label>
  </div>
</div>

state-picker.controller.js

angular.module('umbraco').controller('state-picker.controller', function ($scope, $http, $routeParams, assetsService, contentResource, notificationsService) {
    
     assetsService.loadCss('/App_Plugins/StatePicker/styles.css');
    
     $scope.items = $scope.model.defaultConfig ? $scope.model.defaultConfig.items : $scope.model.config.items;
     
     if ($scope.model.value) {
       var values = $scope.model.value.split(' ');
       for (var y = 0; y < values.length; y++) {
         for (var i = 0; i < $scope.items.length; i++) {
           if ($scope.items[i].value == values[y]) {
             $scope.items[i].selected = true;
           }
         }
       }
     }
    
     $scope.select = function (item) {
       $scope.setValue();
     };
    
     $scope.setValue = function () {
       $scope.model.value = '';
       for (var i = 0; i < $scope.items.length; i++) {
         if ($scope.items[i].selected) {
          $scope.model.value += $scope.items[i].value + ' ';
         }
       }
     };
   });