JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="artistlist">
    <li>Pablo Picasso</li>
    <li>Vincent van Gogh</li>
    <li>Leonardo da Vinci</li>
    <li>Claude Monet</li>
</ul>

CSS

.artistlist li {
    display: inline;
}
.artistlist li:after {
    content: ", ";
}
.artistlist li:last-child:after {
    content: "";
}