If you think of something that's not on this list and it works, let me know!
By using Safari's Bonjour Bookmarks/Favorites anyone can discover your remote. Even without having Reign installed!
Read the guide to set this up.
Use themes to personalize your Spotify remote. Select a background image, or completely change the HTML & CSS.
You can even take it a step further and create a native custom client. Check the developer page for more information.
Some of you might be familiar with Alfred. It's a nifty tool that aims to increase your productivity by executing many tasks using keyboard shortcuts and keywords.
Reign now has it's own Alfred 2 workflow that helps you to remote control Spotify clients super fast, using your keyboard. First download Alfred, then get the workflow and start typing.
Like Reign, the workflow is free and open-source. Contribute on GitHub.