Note:
After any changes it's neccessory to generate changed assets, For that you need to execute build, navigate to the Admin folder containing the package.json file. Open a command prompt in that directory and execute the command "build" as demonstrated below. 
                  
npm run build

Icons

1. Tabler Icons

https://tabler-icons.io/ 
                            
    // ----------------------------------------------------
    // File: Admin/src/assets/scss/style.scss
    // ----------------------------------------------------  
    
    @import "icons/tabler-icons/tabler-icons.css";
    
    // ----------------------------------------------------------------------
    
    <div class="list-group-horizontal">
      <i class="ti ti-mood-happy text-dark fs-6"></i>
      <i class="ti ti-mood-happy text-dark fs-7"></i>
      <i class="ti ti-mood-happy text-dark fs-8"></i>
      <i class="ti ti-mood-happy text-dark fs-9"></i>
      <i class="ti ti-mood-happy text-dark fs-10"></i>
    </div>