JSFiddle - React, Tailwind, and code Playground

HTML

<select>
    <option> one </option>
    <option> two </option>
</select>

CSS

option:after {
    content: " ";
    height: 5px;
    width: 5px;
    background: #c00;
    border-radius: 5px;
    display: inline-block;
}