So the u/thehouseof account posted a ton of what appear to be encrypted messages to the sub r/8d555938976fc8b about two years ago. It looks like they were posting throughout the year 2016. I have no idea if there are more of these encrypted subs.
The sub name looks like it's the first few characters of a line in the sub description : 8d555938976fc8bc672f3e316354d5bf4ebdec6e so if I can figure out how to decode this, perhaps I can find more of these subs.