Wallcat - Enjoy a new, beautiful wallpaper, every day.
Ruffle - An open source Flash player
Splashy - Breathtaking, auto changing wallpaper app for macOS, Windows, Linux, iOS & Android
SuperNova Player - SuperNova Player allows systems to play .SWF files in a standalone player launched from any browser.
Irvue - (previously Unsplash Wallpaper) Gorgeous wallpapers on your Mac.
Lightspark - The Lightspark project