Brutaldon is a brutalist, Web 1.0 web interface for Mastodon. You can use it as a client for any instance. Currently you do not need a separate brutaldon account. It is compatible with almost any web browser, including text-mode browsers like lynx, w3m, or eww.
Screenshots, issues tracker, and source code are available at https://github.com/jfmcbrayer/brutaldon.