Multi Url Picker is available as a built-in property editor in Umbraco 7.14+ and 8.0+
Allows editors to pick and sort multiple urls, it uses Umbraco's link picker which supports internal and external links and media.
Add a new property to your document type and select the Multi Url Picker property editor in the pickers category.
If you're using the models builder, you can access the property on your model e.g. Model.Links if your property alias is links.
@{ var links = Model.Links.ToList(); }
@if (links.Count > 0)
{
  <ul>
    @foreach (var item in links)
    {
      <li><a href="@item.Url" target="@item.Target">@item.Name</a></li>
    }
    </ul>
}If Max number of items is configured to 1
@if(Model.Link != null)
{
  <a href="@Model.Link.Url" target="@Model.Link.Target">@Model.Link.Name</a>
}