Dark and Neon 404 page templates
Dark backgrounds, glowing colors and night-time moods. All 10 are free to download and use, and each one is a single HTML file.
How to use one
Click Download to save the template as 404.html. Open it in any text editor, change the brand name, colors and links, then upload it to your site. The setup guide shows how to make your server use it for every missing page.