I was looking at https://css-tricks.com/single-element-loaders-the-spinner/ to see some other ways of doing spinners, but after seeing that I realized that having fancy spinner loaders just frustrates me. It reminds me of all the time I've spent looking at a spinner and waiting for an app/page/game to load. The fact that a lot of time was put into designing a nice spinner is almost an insult.

I think the optimal spinner might be the simplest possible one, just show something moving/changing to show that the page is still loading.