You can use any icons with font generated by icomoon

<q-tab route="/in" exact replace>
    <span class="icomoon my_custom_icon"><span>In
</q-tab>

@font-face
  font-family 'Icomoon'
  src url('./icomoon.woff') format('woff')
.......................
.icomoon
  font-family 'Icomoon'
.my_custom_icon:before
  content "\e9ac"
.........................

You can use any icons with font generated by icomoon

<q-tab route="/in" exact replace>
    <span class="icomoon my_custom_icon"><span>In
</q-tab>

@font-face
  font-family 'Icomoon'
  src url('./icomoon.woff') format('woff')
.......................
.icomoon
  font-family 'Icomoon'
.my_custom_icon:before
  content "\e9ac"
.........................