… and
sView, a rather good 3D (image+video) player I discovered recently.
Can show almost anything "as" anything – even 3D MVC MKVs. Output (for example) as anaglyph (all 3 versions) or SBS for those who can do parallel view like me.
Available for Linux, Windows, macOS, Android. The Windows version shows an upside-down user interface here, but on Linux it runs just fine. Also has an Ubuntu PPA and a
Github page.